Configurable libp2p transport settings via environment variables

As discussed in [PR #6546](https://github.com/hoprnet/hoprnet/pull/6546#discussion_r1796923428), we should review and update the basic libp2p transport configurations to allow setting them via environment variables.

Requested by @Teebor-Choka.

Comment URL: https://github.com/hoprnet/hoprnet/pull/6546#discussion_r1796923428