#945: Fix portalocker error handling.

Closes #945 (closed)

Related to #1429

This modifies the logic in the central function that captures errors in Autosubmit, used for every autosubmit subcommand. Instead of printing the error and releasing the lock, now it keeps the lock if the error was a portalocker error.

Portalocker is now the only one that locks and unlocks experiments (done automatically via context-manager, when the code finishes or upon a crash/another exception/AutosubmitCritical/etc.). Unless the user or someone/thing deletes the lock file.

• Tested locally running an experiment for one hour, and testing commands that would have released the lock. Used lslocks -p $PID to confirm the lock was never released.
• Added tests