…bt also lock manually selected coins

6d1f513 [rpc] fundrawtransaction, walletcreatefundedpsbt lock manually selected coins (Sjors Provoost)

Pull request description:

  When using `fundrawtransaction` and `walletcreatefundedpsbt` with `lockUnspents`, it would only lock automatically selected coins, not manually selected coins. That doesn't make much sense to me if the goal is to prevent accidentally double-spending yourself before you broadcast a transaction.

  Note that when  creating a transaction, manually selected coins are automatic "unlocked" (or more accurately: the lock is ignored). Earlier versions of this PR introduced an error when a locked coin is manually selected, but this idea was abandoned after some discussion. An application that uses this RPC should either rely on automatic coin selection (with `lockUnspents`) or handle lock concurrency itself with manual coin selection. In particular it needs to make sure to avoid/pause calls with automatic coin selection between calling `lockunspent` and the subsequent spending RPC.

  See bitcoin#7518 for historical background.

ACKs for top commit:
  meshcollider:
    Code review ACK 6d1f513
  fjahr:
    Code review ACK 6d1f513

Tree-SHA512: 8773c788d92f2656952e1beac147ba9956b8c5132d474e0880e4c89ff53642928b4cbfcd1cb3d17798b9284f02618a8830c93a9f7a4733e5bded96adff1d5d4d

92326d8 [rpc] add send method (Sjors Provoost)
2c2a144 [rpc] add snake case aliases for transaction methods (Sjors Provoost)
1bc8d0f [rpc] walletcreatefundedpsbt: allow inputs to be null (Sjors Provoost)

Pull request description:

  `walletcreatefundedpsbt` has some interesting features that `sendtoaddress` and `sendmany` don't have:
  * manual coin selection
  * outputting a PSBT (it was controversial to add this, see #18201)
  * create a transaction without adding to wallet (which leads to broadcasting, unless `-walletbroadcast=0`)

  At the same time `walletcreatefundedpsbt` can't broadcast a transaction, which is inconvenient for simple use cases.

  This PR introduces a new `send` RPC method which creates a PSBT, signs it if possible and adds it to the wallet by default. If it can't sign all inputs, it outputs a PSBT. If `add_to_wallet` is set to `false` it will return the transaction in both PSBT and hex format.

  Because it uses a PSBT internally, it will much easier to add hardware wallet support to this method (see #16546).

  For `bitcoin-cli` users, it tries to keep the simplest use case easy to use:

  ```sh
  bitcoin-cli -regtest send '{"ADDRESS": 0.1}' 1 sat/b
  ```

  This paves the way for deprecating `sendtoaddress` and `sendmany` though there's no rush. The only missing feature compared to these older methods is adding labels to a destination address.

  Depends on:
  - [x] #16377 (`[rpc] don't automatically append inputs in walletcreatefundedpsbt`)
  - [x] #11413 (`[wallet] [rpc] sendtoaddress/sendmany: Add explicit feerate option`)
  - [x] #18244 (`[rpc] have lockUnspents also lock manually selected coins`)

ACKs for top commit:
  meshcollider:
    Light re-utACK 92326d8
  achow101:
    ACK 92326d8 Reviewed code and test, ran tests.
  kallewoof:
    utACK 92326d8

Tree-SHA512: 7552ef1b193d4c06e381c44932fdb0d54f64383e4c7d6b988f49d059c7d4bba45ce6aa7813e03df86360ad9dad6f3010eb76ee7da480551742d5fd98c2251c0f

92326d8 [rpc] add send method (Sjors Provoost)
2c2a144 [rpc] add snake case aliases for transaction methods (Sjors Provoost)
1bc8d0f [rpc] walletcreatefundedpsbt: allow inputs to be null (Sjors Provoost)

Pull request description:

  `walletcreatefundedpsbt` has some interesting features that `sendtoaddress` and `sendmany` don't have:
  * manual coin selection
  * outputting a PSBT (it was controversial to add this, see bitcoin#18201)
  * create a transaction without adding to wallet (which leads to broadcasting, unless `-walletbroadcast=0`)

  At the same time `walletcreatefundedpsbt` can't broadcast a transaction, which is inconvenient for simple use cases.

  This PR introduces a new `send` RPC method which creates a PSBT, signs it if possible and adds it to the wallet by default. If it can't sign all inputs, it outputs a PSBT. If `add_to_wallet` is set to `false` it will return the transaction in both PSBT and hex format.

  Because it uses a PSBT internally, it will much easier to add hardware wallet support to this method (see bitcoin#16546).

  For `bitcoin-cli` users, it tries to keep the simplest use case easy to use:

  ```sh
  bitcoin-cli -regtest send '{"ADDRESS": 0.1}' 1 sat/b
  ```

  This paves the way for deprecating `sendtoaddress` and `sendmany` though there's no rush. The only missing feature compared to these older methods is adding labels to a destination address.

  Depends on:
  - [x] bitcoin#16377 (`[rpc] don't automatically append inputs in walletcreatefundedpsbt`)
  - [x] bitcoin#11413 (`[wallet] [rpc] sendtoaddress/sendmany: Add explicit feerate option`)
  - [x] bitcoin#18244 (`[rpc] have lockUnspents also lock manually selected coins`)

ACKs for top commit:
  meshcollider:
    Light re-utACK 92326d8
  achow101:
    ACK 92326d8 Reviewed code and test, ran tests.
  kallewoof:
    utACK 92326d8

Tree-SHA512: 7552ef1b193d4c06e381c44932fdb0d54f64383e4c7d6b988f49d059c7d4bba45ce6aa7813e03df86360ad9dad6f3010eb76ee7da480551742d5fd98c2251c0f

…ed coins

Summary:
Previously only automatically selected coins were locked when lockUnspents is set.
It now also locks selected coins.

This is a backport of [[bitcoin/bitcoin#18244 | core#18244]]

Test Plan: `ninja all check-all`

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D10144