Implement lock_wait_timeout option for the source database (MySQL)

[markosutic]

Is your feature request related to a problem? Please describe.
For the initialization process pg_chameleon will issue FLUSH TABLES WITH READ LOCK on a source database (MySQL) to get transactional snapshot. This action can be blocked with long running transaction on a table and pg_chameleon could wait very log time if lock_wait_timeout is not configured.
It would be nice to be able to specify lock timeout as FTWRL could be risky operation in some production workloads.

Describe the solution you'd like
Implement lock_wait_timeout option for source (MySQL) database. It would be nice to be able set lock_wait_timeout just for pg_chameleon session not affecting others.

Also, I think current config is not intuitive as I would assume that lock_timeout specified under the source database (MySQL) is related to the locks on the MySQL not target database (Postgres).

Thank you