feature: separate job_factory, introduce auto_remove option and custom server name_templates

[mj0nez]

Hi,

Thank you for this project! I've recently adopted it at work but had to do some changes, which could be useful.

This PR introduces the following changes:

• introduce name_template to customize the server naming; which allows more speaking job names
• add auto_remove_jobs config to remove Nomad jobs after the server stops (defaults to False)
• extracted job_factory from start to allow customization by server operators;
  useful if the spawning does not require user interaction, you want a more homogenous cluster or there are some defaults you want to set
• extracted fetch_from_service_provider from `start;
  to allow custom logic to fetch the spawned server's address and port (e.g. you want to fetch a consul service via the Nomad API)
• added some recipes and improved the docs

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[mxab]

Hi @mj0nez, thank you very much for you're contribution. I'm going to review asap.

Very excited that this project is adopted by others :)

[mxab]

@mj0nez thank you, the PR looks awesome!