Type signatures for `.create_table()` and `.create_table_sql()` and `.create()` and `Table.__init__`

> Adding type signatures to `create_table()` and `.create_table_sql()` is a bit too involved, I'll do that in a separate issue.

_Originally posted by @simonw in https://github.com/simonw/sqlite-utils/issues/312#issuecomment-896200682_