allow PullsAllowMerge/PullsAllowRebase to be enabled via configuration

[jstrachan]

I wonder if we could add a configuration so that we can enable the flags PullsAllowMerge/PullsAllowRebase OOTB on all newly created repositories?

Then whether we create new repositories via the web UI or REST API they could come with some of these boxes enabled?

Otherwise its painful; folks have to go into the web UI and tweak newly created repos if they want them to work with PRs:

I originally raised this as an issue against the REST API - but it turns out there isn't a REST API I can see to configure the repository options and this issue affects repos created via the web UI too
go-gitea/go-sdk#100

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs during the next 2 weeks. Thank you for your contributions.

[adelowo]

This is enabled by default this days I believe

[jstrachan]

@adelowo ah awesome thanks!

[apricote]

For reference, all merge styles are enabled for new repos here https://github.com/go-gitea/gitea/blob/master/models/repo.go#L1311