Reorganize the frequency plans repository

[adriansmares]

Summary

Based on our earlier call regarding newer regional parameters, we have discussed that the following changes should be done to this repository:

• [ ] We should start versioning the repository (one branch per version)
• [ ] The gateway frequency plans should be separated from the end device frequency plans
  • The gateway frequency plans don't have to be versioned (on a per regional parameters basis) - they represent the latest version, and data rate ranges are not required
• [ ] The definition of the frequency plans should be moved to this repository. This allows CI to be added and the content of the frequency plans to be validated.

Why do we need this?

In order to support newer regional parameters versions.

What is already there? What do you see now?

Only master, containing frequency plans combining both gateways and end devices.

What is missing? What do you want to see?

• One branch per version
• Top level folders for end device frequency plan definitions, and for gateway frequency plan definitions
• A Go package that exposes the schema for these definitions

Can you do this yourself and submit a Pull Request?

Can review and assist when needed.

[adriansmares]

References https://github.com/TheThingsNetwork/lorawan-stack/issues/4196

[htdvisser]

Removing milestone since https://github.com/TheThingsNetwork/lorawan-stack/issues/4196 is still unplanned

[ysmilda]

I agree that we need to version the plans, but I'm not sure that doing that by different branches will be the way to do that.

Currently the stacks imports the frequency-plans as a submodule. When going with branch versioning the stack won't easily be able to import all versions this way. Wouldn't folder based versioning fit better?