Make it easier to plug in other providers and add a mock provider (#8)

Merge pull request #6 from gzuidhof/fix-stop-watching-server-when-rem…

…oved

Stop watching server when it is removed

Merge pull request #5 from gzuidhof/prevent-overlapping-updates

Prevent overlapping resources updates

Merge pull request #4 from gzuidhof/fix-no-more-changes-after-resourc…

…es-changed

Fix no more changes after resources changed, improve notifications (add direct links)

Merge pull request #3 from gzuidhof/spell-out-readonly-mode

Print version in first message

Merge pull request #2 from gzuidhof/fix-ipv6-testing-for-hetzner

Fix IPv6 selection for Hetzner servers

Merge pull request #1 from gzuidhof/fix-map-concurrent-access

Fix concurrent access to update

Print failing check ID when something goes unhealthy

Fix ipv4 and ipv6 check ID clash, shorter notifications

Fix groups.port config validation