Fixes #1411 - Remove Biggin Approach

[Liaely]

Fixes #1411

Summary of changes

Removes Biggin Approach.
Changes Tower callsign from "Biggin Tower" to "Biggin".
Adds KB AIR to EGLF VACS profile.

[luke11brown]

From the above excerpt, from what I can see the approach position still exists. But likely that a single controller will work APP and TWR. The question is, how to handle it on VATSIM?

If I'm S3+ and want to do Biggin Approach, offering a basic/procedural service, surely I should be able to open EGKB_A_APP on the TWR frequency?

[BenWalker01]

The VACS profile changes can be dropped

[hazzas-99]

I agree @luke11brown, I'm not convinced with this approach. The 'Biggin' controller will still be approach-rated. S2s don't have the appropriate training to operate 'approach-in-the-tower' so on VATSIM I think we should either stick with split positions or remove Tower and make EGKB_A_APP the position to be known as 'Biggin'.