Add mig support in specs

[cmd-ntrf]

No description provided.

[mboisson]

For the documentation, mig flavors need quotes, otherwise:

╷
│ Error: Missing key/value separator
│ 
│   on main.tf line 82, in locals:
│   82: 	    mig = { 1g.5gb = 2, 2g.10gb = 1, 3g.20gb = 1 }
│ 
│ Expected an equals sign ("=") to mark the beginning of the attribute value.
│ If you intended to given an attribute name containing periods or spaces,
│ write the name in quotes to create a string literal.