General repo setup

[rainest]

Generic new repo setup tasks tracking in relation to Kong/deck#1060

• Access settings and CODEOWNERS copied from deck repo. Thijs was not copied, since his account is part of team-deck and had more permissions from that than it did individually (Admin versus Write).
• Confirm if we want the same CODEOWNERS and access settings here, or if we need changes.
• CLA needs to be set up. This looks like it requires some work on the CLA provider side, after which we can more or less copy the deck repo settings from the Webhook section.
• CodeQL needs to be set up. Github won't let me do so until it thinks this repo is Golang.
• Secrets need to be sorted out. Can't copy these from deck, and unsure which all we'll need (the testing situation here will probably be different and I don't expect this repo will push Docker artifacts).

[rainest]

CLA is apparently screwy and ignores the "Kong org members don't need it" setting. Unfortunately nobody appears to own our CLA integration or understand why this happens.