use "schema" as "search_path" connection option

[62mkv]

This change adds an alias currentSchema for schema configuration parameter; and uses this value as a value for "search_path" connection option (instead of executing SET SCHEMA TO command upon connection)

[resolves #271 ]

Make sure that:

• You have read the contribution guidelines.
• You have created a feature request first to discuss your contribution intent. Please reference the feature request ticket number in the pull request.
• You use the code formatters provided here and have them applied to your changes. Don't submit any formatting related changes.
• You submit test cases (unit or integration tests) that back your changes.

Issue description

Closes #271

New Public APIs

Additional context

[62mkv]

hi @mp911de is to too bad for review? just to clarify: I've left one action (about formatters) unchecked, because when I applied (or thought to have applied) the recommended style and ran the Code Reformat action in IntelliJ, the code was re-formatted heavily so I had to manually adjust it.

It still feels that making something like (in PostgresqlConnectionFactoryProvider.java)

Map<String, String> options;
if (connectionFactoryOptions.getValue(OPTIONS)) instanceof String) {
   options = tryParseOptions(connectionFactoryOptions.getValue(OPTIONS));
} else {
   options = connectionFactoryOptions.getValue(OPTIONS);
}

might be a more generic way to address this (and similar) issues. What do you think ?

[mp911de]

No worries. We weren't able yet to review this PR as we're busy with other projects.

[mp911de]

Thank you for your contribution. That's merged, polished, and backported now.