[FEATURE] Adding support for PostgreSQL

[M4ST3RX]

Issue or feature explanation

This feature adds support for PostgreSQL database connections. See #46

Proposed solution/change

See commits for the changes. Few important bits:

• Created Prequel facade as a universal query builder
• Changed usage of DB to custom PDB facade
• Added an argument to DatabaseConnector::getConnection so PostgreSQL can query multiple databases.
• Added getTableData function to retrieve the rows of a table.

[QuintenJustus]

Looks good!

[James-N-M]

@M4ST3RX next time you take on a issue like this lets pair it, I've love to learn how you went about it 💯