SOQL-related checks aren't recognized in "Database.query('')" format

[VarS311]

The node visitor isn't able to recognize SOQL statements when they are invoked by Database.query('...') because the content of the query is tokenized as a String before the parser has a chance to relate it to the SOQL_EXPRESSION rule, so the checks related to SOQL won't pop-up.

After some analysis, we figured the best way to solve this issue could be by re-parsing the value of what is recognized as a STRING, and then we could apply the same checks to the new smaller "pseudo-tree" that will be the result of the new parse process.