Add an optional `order_by` parameter to the `user.ListMyRepos`
handler (which handles the `/api/v1/user/repos` route), allowing a user
to sort repos by name (the default), id, or size.
The latter will be useful later for figuring out which repos use most
space, which repos eat most into a user's quota.
Signed-off-by: Gergely Nagy <forgejo@gergo.csillger.hu>
250f87db59