PBM-1308: Improve read/write concern validation

[boris-ilijic]

Fix for https://perconadev.atlassian.net/browse/PBM-1308 .

Following validation are added:

mongodb://pbmuser:[email protected]:30001/?authSource=admin&w=1
mongodb://pbmuser:[email protected]:30001/?authSource=admin&w=1&readConcernLevel=majority
-----
Exit: connect to PBM: create mongo connection: invalid connection string option: ReadConcern majority and WriteConcern 1 is not allowed

mongodb://pbmuser:[email protected]:30001/?authSource=admin&w=1&readConcernLevel=available
mongodb://pbmuser:[email protected]:30001/?authSource=admin&w=1&readConcernLevel=snapshot
mongodb://pbmuser:[email protected]:30001/?authSource=admin&w=1&readConcernLevel=linearizable
mongodb://pbmuser:[email protected]:30001/?authSource=admin&w=1&readConcernLevel=abc
-----
Exit: connect to PBM: create mongo connection: invalid connection string option: ReadConcern level is not allowed

In addition read/write concern info is added in pbm-agent startup log info:

mongodb://pbmuser:[email protected]:30001/?authSource=admin
-----
...
GoVersion: go1.22.1
2024-05-15T10:23:15.000+0200 I starting PITR routine
2024-05-15T10:23:15.000+0200 I node: rs0/rs01:30001
2024-05-15T10:23:15.000+0200 I conn level ReadConcern: majority; WriteConcern: majority
2024-05-15T10:23:15.000+0200 I listening for the commands
...

mongodb://pbmuser:[email protected]:30001/?authSource=admin&w=1&readConcernLevel=local
-----
...
GoVersion: go1.22.1
2024-05-15T10:21:36.000+0200 I starting PITR routine
2024-05-15T10:21:36.000+0200 I node: rs0/rs01:30001
2024-05-15T10:21:36.000+0200 I conn level ReadConcern: local; WriteConcern: 1
2024-05-15T10:21:36.000+0200 I listening for the commands
...