When recovering with `--no-get-wal` and `--target-lsn`, bring only the WALs up to the specified LSN

[barthisrael]

Previous to this PR, when the user specified --target-lsn and --no-get-wal in barman recover command, Barman was copying all WAL files from Barman to Postgres.

As we are able to infere the required WAL files based on the specified --target-lsn, this PR changes Barman so it copies only the required WAL files instead of them all.

Notes:

• We also added a missing unit test to cover the case where --target-xid is specified;
• This PR is based on #951. That PR needs to be merged before this PR.

References: BAR-190.