Add possibility to incentivize merged PRs directly from Github

First discussion happend in Kusama Direction.

The goal should be, to make it possible to incentivize PR-submitters with Treasury-KSM when the PR gets merged.

I first proposed to create an offchain worker that pulls the merged Github PRs, tries to find the submitter's address and spends a small amount of KSM to him. Maybe locked for some days to prevent abuse and offer the possibility to slashing.

In the discussion there was a big decline for an automatic solution, because of the possible huge amount of low-quality/low-impact PRs from the community and the increased amount of work for the reviewers.

Then there was a discussion about, what a low-quality/low-impact PS is. My argument was that the incentive should be just as big to give the user a little kick to create a PR for, e.g. a typo, a small issue on the webpage... that otherwise was not reported due to the laziness of the finder.

Then there was a proposal to maybe write a Github-Bot that scans for trigger lines like:

tip: 0.001 5EkgL7gLn5tnUsXQEyTuDuPfQw119tTFKE5YDvtEHuZcC25K

from the reviewer to trigger the payout.

One Problem that remains, was that only the Council has access to the Treasury and we don't want to call the council for every code-tipping. So my proposal was to create a Pot/Account, filled by the Council on a demand basis, that the Github-Bot can spend.

I'd like to continue the discussion here as I see real benefits on such a mechanism.