The Argument struct.

It will encompass all data read from the command file for each argument.

• :name - name of the argument as read from the file
• :canonical_name - string representation of the name
• :type - type of the argument
• :optional - boolean value indicating if the argument is optional
• :multiple - boolean value indicating if the argument can be used multiple times
• :enum - possible values if the argument is enumerable
• :variadic -
• :command - command that must preceed the argument

Function to split the arguments that are optional or commands from the required ones.

It will receive a list of Comredis.Command.Argument structs and return a tuple with the required arguments first and then the others.