Updated the operator, fixing a bug with the database connection, where if a network is deleted and still has pods, it would break it

Updated l2sm database schema and operator to go along with it. Now there are more constraints in the database and errors are handled accordingly, so the application is more robust against errors

The source code directory has been moved from ./build to ./src.

This change was made to improve project organization and follow best practices.

Fixed loop  that occured when two bridges joined together and the switch, forming a loop that would take all the CPU usage from process systemd-networkd

general: added bridge interfaces between switches and pods. \n This is with the objective  of easing and automating the installation of l2sm, without having the user to configure the ip addresses in their machine

BUG FIX: switch ip now is saved correctly in the database, using a better trigger for the ip assigning event