Indicate whether plan is applicable to gateways / end devices

[htdvisser]

Summary

For each plan we should indicate whether it's applicable to end devices and/or gateway.

What is already there? What do you see now?

In the Console you can now select both the EU_863_870 plan and the EU_863_870_TTN plan when registering a gateway. For gateways, these plans are equivalent, but users don't know that, which makes it confusing.

What is missing? What do you want to see?

We should only show relevant plans when registering gateways / end devices.

How do you propose to implement this?

We'd need to indicate in each frequency plan (or perhaps in the index) whether the plan applies to gateways, end devices or both.

[NicolasMrad]

#38