WIP: Add basic gerrit support

[KonradStanski]

This commit adds support for gerrit repos. It will either fetch all repos, or the specified ones. Branch fetching is supported Tags are not yet supported Auth is not yet supported (not necessary for default gerrit setup) Need to add useage of gerritkit rest api npm module

DO NOT MERGE YET PLEASE SQUASH ON MERGE

[KonradStanski]

Should we add the yarn.lock file to gitignore?

[KonradStanski]

This works as is with public gerrit instance. Try:

{
    "$schema": "https://raw.githubusercontent.com/sourcebot-dev/sourcebot/main/schemas/v2/index.json",
    "repos": [
        {
            "type": "gerrit",
            "url": "https://review.opendev.org",
            "limit": 5,
            "exclude": {
                "projects": [
                    "All-Users",
                    "All-Projects"
                ]
            },
            "revisions": {
                "branches": [
                    "refs/heads/v2.0",
                    "refs/heads/v2.1"
                ],
                "tags": [
                    "applier-v2.1.0"
                ]
            }
        }
    ]
}

Ignore tags, it's not implemented yet.

[brendan-kellam]

Should we add the yarn.lock file to gitignore?

No we want yarn.lock to be checked into source control. See here.