* PostgreSQL: FIx multiple results handling
- Added tests for handling multiple result sets, including compatible and incompatible structures, ensuring no panics occur.
- Improved `convertResultsToFrame` function to validate column compatibility and handle null values correctly.
- Introduced a new helper function `convertPostgresValue` for converting raw PostgreSQL values to appropriate Go types.
- Added comprehensive unit tests for `convertResultsToFrame` covering various scenarios including row limits and mixed result types.
* Add more test case
* Create libpqToPGX feature toggle
* Refactor PostgreSQL datasource to support PGX with feature toggle
- Updated `ProvideService` to accept feature toggles for enabling PGX.
- Modified integration tests to use the new PGX connection method.
- Introduced new functions for handling PGX connections and queries.
- Enhanced TLS configuration handling for PostgreSQL connections.
- Updated existing tests to ensure compatibility with PGX and new connection methods.
* Update PostgreSQL datasource to enhance connection pooling and error handling
- Increased `MaxOpenConns` to 10 in integration tests for improved connection management.
- Refactored connection handling in `newPostgresPGX` to return a connection pool instead of a single connection.
- Updated health check error handling to utilize context and feature toggles for better error reporting.
- Adjusted `DisposePGX` method to close the connection pool properly.
- Enhanced query execution to acquire connections from the pool, ensuring efficient resource usage.
* Cleanup
* Revert postgres_test unnecessary changes
* Rename feature toggle from `libpqToPGX` to `postgresDSUsePGX`
* Add null check to dispose method
* Fix lint issues
* Refactor connection string generation
* Address comment in health check file
* Rename p to pool
* Refactor executeQueryPGX and split into multiple functions
* Fix lint issues
* The returning error message from PGX is enough no need to separate the error code.
* Move TLS handling to newPostgresPGX function
* Disable ssl for integration tests
* Use MaxIdleConns option
* Remove old feature toggle
* Rename`generateConnectionConfigPGX` to `generateConnectionStringPGX`
* Add back part of the error messages
* Don't show max idle connections option when PGX enabled
* Address comments from Sriram
* Add back Sriram's changes
* PostgreSQL: Rework tls manager to use temporary files instead (#105330)
* Rework tls manager to use temporary files instead
* Lint and test fixes
* Update pkg/tsdb/grafana-postgresql-datasource/postgres.go
Co-authored-by: Ivana Huckova <30407135+ivanahuckova@users.noreply.github.com>
* Update betterer
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Co-authored-by: Ivana Huckova <30407135+ivanahuckova@users.noreply.github.com>
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Co-authored-by: Ivana Huckova <30407135+ivanahuckova@users.noreply.github.com>
