Base class for CRUD: Store and retrieve MySQL records for CRUD actions

This class can store and retrieve MySQL records for CRUD actions.

It can connect to a MySQL database using the MySQLi extension and performs several actions used to implement CRUD (Create, Read, Update and Delete) interfaces.

Currently it can retrieve all the records of a given table, retrieve or delete a record of a table with a given ID, create a new record of the table, update the values of the record of a table with a given ID.