LE Audio: PACS: Server change location

[Thalley]

Is your enhancement proposal related to a problem? Please describe.
The PACS location values are currently just Kconfig options, but as the capabilities can change, so can the location.

Describe the solution you'd like
The location should be writable by the PACS server. One way of doing that is to retrieve the location value from the application, similar to how PAC records are, instead of storing it in the service implementation.

Describe alternatives you've considered
Could also keep the location in the service implementation and provide a function to write it.

Additional context
N/A