Update of volvooncall component

[molobrakos]

Description:

• Converted component to async (review requested)
• Updated external dependency lib (also now async), and moved some logic there.
• Support for more entities (engine start switch etc)
• Added mutable configuration option (default true), which can be set to false to not display any "dangerous" controls for unlocking vehicle, start engine, start heater etc.
• Related: The external dependency (https://github.com/molobrakos/volvooncall) can now alternatively run separate (e.g. on a different host) feeding data into (and consuming from) Home Assistant over MQTT.

Pull request in home-assistant.io with documentation (if applicable): home-assistant/home-assistant.io#7647

Example entry for configuration.yaml (if applicable):

volcooncall:
  username: !secret voc_username
  password: !secret voc_password
  scandinavian_miles: yes
  mutable: no

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• New dependencies have been added to the REQUIREMENTS variable ([example][ex-requir]).
• New dependencies are only imported inside functions that use them ([example][ex-import]).
• New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

[MartinHjelmare]

This looks great! Let me know when it's out of WIP, and I'll take a final look.

[MartinHjelmare]

Very nice! Can be merged when last comment is addressed, build passes and docs PR is linked in description.

[molobrakos]

What about async_will_remove_from_hass, is that needed here as well? (Noticed that when looking at https://github.com/home-assistant/home-assistant/pull/18780/files) @MartinHjelmare

[MartinHjelmare]

Until we implement config entries for volvooncall, or explicitly remove entities, async_will_remove_from_hass will never be needed. So it's optional until those circumstances.

[MartinHjelmare]

For future PRs, to make it easier for readers to track changes, please don't squash after review has started. We will squash when we merge.

[MartinHjelmare]

It looks like, we could move this out one level, so that's it not defined each time we run discover_vehicle.

[MartinHjelmare]

We can clean that up later, if wanted.