[Snapclient] Add `--type` option to specify the type of the client

[badaix]

Possible types could be

• computer
• tablet [default on Android tablet]
• smartphone [default on Android phone]
• speaker [default]
• browser [default in Snapweb]
• lightbulb
• lightstrip [if fed into something like LedFX]

Depending on the type, control clients could show different UI elements