berrywm: mouse resize/move with multiple modifiers

[Sidd-Dino]

Berry currently accepts only one modifier for resize/move_mask.
This version allows using one or more modifiers to resize/move
Allowing a wide selection of key combinations.

Modifiers:                                                                       
shift, lock, ctrl, mod1, mod2, mod3, mod4, mod5                                  
                                                                                 
Examples:                                                                        
berryc resize_mask "mod1"             --> alt (default)                          
berryc resize_mask "shift|mod1"       --> shift + alt                            
berryc resize_mask "ctrl|shift|mod1"  --> ctrl + shift + alt                     
                                                                                 
berryc move_mask "mod4"               --> super (default)                        
berryc move_mask "shift|mod4"         --> shift + super