Introduce ScAC Low position

[hazzas-99]

What are the suggested changes?

Introduction a "Scottish Low" position on frequency 124.500

This will cover the following real world sectors:

• Moray Low
• Hebrides Low
• Westcoast
• Tay
• Antrim
• Galloway (N&S)
• Talla (N&S)

We haven't actually got a Westcoast or Tay sector in our sector file, because they'd never be split off on their own.

Westcoast mostly sits below the Central and Rathlin sectors, so they can just be divided at 255 with different ownership orders, creating a Central Low and a Rathlin West Low.

Forming a Tay sector (which sits under Montrose, but isn't entirely geographical coincident) will be slightly more complex. The sector data is offered up by NATS here. Our Tay won't be like the real one, as it has a bit of Westcoast's airspace in the top left corner:

ScAC Low should have priority over all sectors except Antrim and the TMA ones - if STC_A or STC_W/E/STC_CTR log on, they should have higher priority than a ScAC Low.

NB: COPX can be checked in a separate issue.

Sources

Event-only sector.

Files to be changed

Various

[lennycolton]

@AleksMax Are you still working on this?

[AleksMax]

Oops, forgot to drop this, all yours @lennycolton