Migrate Mquery to typed config library

[msm-code]

Your checklist for this pull request

• I've read the contributing guideline.
• I've tested my changes by building and running mquery, and testing changed functionality (if applicable)
• I've added automated tests for my change (if applicable, optional)
• I've updated documentation to reflect my change (if applicable)

This is a WIP draft PR for migration of mquery's config from current config mechanism (config.py) to typed-config.

It doesn't take configuration from redis to the config file yet. It's backwards compatible for docker and kubernetes users (i.e. ENV config didn't change). Despite this, it's still technically backward incompatible for users who use bare metal mquery and edited their config.py

Fixes #320
Fixes #318
Fixes #261

[msm-code]

Ok, i'm feeling lucky.

I'm submitting this PR for review and maybe merging. This changes the current mquery configuration mechanism from editing config.py file, to a "real" config file like this (mquery.ini):

[redis]
host=redis-server.example.com

[mquery]
backend=tcp://ursadb-server.example.com:9281
plugins=plugins.archive:GzipPlugin

This solution has some downsides:

• For some of the users this is likely to break backward compatibility.
• ...actually I think that's all.

Despite this, I like it because:

• It's much cleaner and we save some boilerplate.
• Installation procedure is easier thanks to good defaults (no need to copy and edit files before first use).
• It's backward compatible for docker and kubernetes deployments
• When it's not backward compatible, affected users will see merge conflicts and know that they need to migrate.
• In the future I'll migrate mquery's auth config from redis to this file, bringing more redability and usability benefits.

I've also added a signifcant amount of documentation, to explain mquery config. But this chnage will have to be stressed in the release notes, so users that decide to upgrade know to be careful about that.

[nazywam]

This wasn't just used for debugging and we're leaving this in, right?

[msm-code]

This should've been a separate PR... But yeah, this is very much intended to stay. Without this, docker-compose logs are not available in the CI when something crashes.

[msm-code]

Resolved discussions, squashed... Just realised that I should make it possible (or document) to configure mquery with a config-file even when docker-compose is used. Not sure how to do this correctly, will handle this tomorrow.

Edit: actually docker users should configure their instance with environment vars or mount the config themselves, so that's not applicable.