New tag: Mobile coverage / connectivity

[killakalle]

I would like to request new tags to describes a crag's mobile coverage or mobile speed, e.g.

• Good connectivity
• Medium connectivity
• Low or no connectivity

There are several situations where this information would be helpful

• Climbers with professions where they can be "on call", e.g. doctors, system admins, etc., want to know whether they'll be reachable by phone
• Before visiting a new crag, it's helpful to know whether crag information can be accessed on the fly or whether it should be downloaded upfront
• ...possibly more...