config.yaml params for database limitations - MaxPaths, MaxTableColumns, MaxTableIndices

[asmyasnikov]

Related issue #31303

I work on the PostgreSQL compatibility layer for YDB.
Some PostgreSQL-based software exceeds our default limits and requires creating more tables, columns, and indexes than the default limits allow.

These limits are currently defined by database parameters, but they are difficult to change, and end users cannot adjust them themselves.

I think these parameters should be easy for a database administrator to configure at the database layer