Stop relying on the master version of Psalm

Mark every exception as immutable

I just got bitten by a bug on master at
https://github.com/doctrine/sql-formatter/pull/43#issuecomment-615576443,
and there are good chances we have the bug on the Dbal too. Anyway, it
only makes sense to use the same version as in the vendors.

Reworked LoggingTest to be able to test Statement::executeUpdate()

Remove baseline

null contradicts the phpdoc

For some reason a low version crashes Psalm.

Setup static analysis with Psalm

This should make it easier to work with Composer from machines using
different versions of PHP than the lowest one we use in the CI.

Fix parsing column comments on SQLite

Deprecate EchoSQLLogger

Upgrade to PHPStan v0.12

Additionally, set the new value and get the old one in one ini_set() call.

By either defining their types or renaming to match parent class (or
interface).

Allowing us to use more advanced checks and have full generic support.

This also adds a baseline file, since we have new violations being
reported but don't want to address them right now.