promotions endpoint for anonymous requests

[enekofb]

raised at the back of this thread

weaveworks/weave-gitops-private#76 (comment)

to ensure that we have aligned design and implementation around supporting anonymous requests for promotions endpoint

AC

• Understood whether there is any non-development scenario that this feature would be required with security tradeoffs identified

• At the back of previous understanding adjust design, implementation and documentation as required

[lasomethingsomething]

Closing for age of issue and other competing priorities taking precedence -- we can reopen if this becomes urgent for our customers