FIRST MR : Add class to strucutre the command and basic function

[0.11.0] - 2022-02-10

Added

• Add the execute() function to execute a command of a Request objects.
• Add the min() function to generate the MIN subcommand of a request.
• Add the max() function to generate the MAX subcommand of a request.
• Add the aand() function to generate the ADD subcommand of a request.
• Add the where() function to generate the WHERE subcommand of a request.
• Add the ffrom() function to generate the FROM subcommand of a request.
• Add the select() function to generate the SELECT subcommand of a request.
• Add operator function (gt, lt, ge, le, eq, ne) to get the correct operator for quest like : name = "toto" or mass > 50.
• Add class Request, _Command, _CommandType and MagicDotPath to construct the request command.
• Add function to close a connection to a database.
• Add functions to connect and get cursor to a data base.