Make self-update and doh-dot the default examples

[ragibkl]

At the moment, we have 3 different examples to run the adblock server, and 3 different image versions. I think that is too much, and best to just consolidate the examples and the different dns versions.

The logs server should just reduce to 1 image as well.

• [x] Should make self-update the default behaviour of dns. I think image tag should just be latest, and we can drop the other tags. User should able to override behaviour with environment variables
• [x] Should consolidate dns into single folder, and have less scripts to maintain
• [x] Should make usage with dnsdist the default example. Deprecate the previous logs-viewer image
• [x] With docker hub pull limits, should deprecate watchtower as well, or reduce the pull frequency to just once a day. Actually with self-update, we probably don't need watchtower anymore.
• [x] Should update readme to make it simpler to run

[ragibkl]

Ok, that went well. I did a lot here already. Closing this for now since I'm not sure what else to do.