Feature: Add check for overlapping xor and and groups

[tinytyranid]

This adds a check to make sure that xor and and groups are not overlapping with more than one as promised in #442

[alecthomas]

Apologies for the delay, this slipped my mind.

[alecthomas]

BTW I just used the and functionality today and it was super useful:

🐚 ~/dev/ftl $ ftl profile new --remote http://w3.org test
🐚 ~/dev/ftl $ ftl profile new --local test
Usage: ftl profile new <name> [flags]
Run "ftl profile new --help" for more information.

ftl: error: --local and --secrets and --configuration must be used together

[tinytyranid]

I'm happy to hear that it is already useful 🙂