Add merge on green

[SD10]

We can take Orta's merge on green for use in Moya

I was thinking of having the following two behaviors:

1. Merge on green

• If comment from org member contains phrase "Merge on green"
• PR gets labeled as on green: merge
• If CI passes and it contains the label, auto merge

2. Merge on green and delete

• Same as above but use the phrase "Merge on green and delete"
• Use the label on green: merge&delete
• Protected branches are master and development

[orta]

Peril has the same access as any user WRT deleting protected branches, so you shouldn't need to add code around that

[SD10]

My reasoning behind this was a scenario where the development branch was not protected and not wanting to delete that branch as it is a staging area for future PRs. This is probably a small edge case in retrospect