Plant skeleton of release notes for 0.11.0
Plant skeleton of release notes for 0.11.0

* PR 933 re enabling debug API endpoints by configuration mentioned in
  separate line;

* PRs 937 and 938 re fast_integration env: not mentioned as not
  user-visible;

* Fix for PoW verification crashes (PR 936): considered in the
  catch-all item "Improves the stability of the testnet".

aeternity/epoch,aeternity/epoch,aeternity/epoch,aeternity/epoch