Add support for a Pushover alerter

[kylemart]

Adding support for notifications via https://pushover.net/.

[EricJMarti]

docker_run.bash's command line arguments are getting pretty complicated.. how do you feel about requiring users to configure this type of alerter via a YAML alerter config?

[kylemart]

docker_run.bash's command line arguments are getting pretty complicated.. how do you feel about requiring users to configure this type of alerter via a YAML alerter config?

I think it would make sense to restrict alerter configuration to a YAML config 🤔The YAML alerter config section could be made generic, something like:

alerters:
  - name: pushover
    configure:
      api_token: APITOKEN
      user_key: USERKEY
  - name: discord
    configure:
      ...

(Side-thought: You could also auto-generate documentation by dynamically loading the concrete alerters, and creating a yaml template based off the required kwargs like I depicted in the above code block.)

And of course, when it comes to loading alerters, loading an instance could be something like:

alerter = AlerterFactory.get_class(config['name']).initialize(config['configure'])

[mgt20]

I would find use out of this too. I was able to replicate the changes from kylemart:kylemart/pushover-support into a local copy (have yet to create a fork) I made of EricJMarti:main while avoiding conflicts (such as adding new args getopts to docker_run.bash for user_key and api_token, I used "u" and "y", respectively).

I was not able to get this to run with either inline arguments or using the alerters.yaml file. In both cases, I'm getting an:
Exception: the "pushover" alerter type does not exist in the registry

Is there something obvious I'm missing? Would love to help implement this feature if possible (though I'm a bit elementary in Python and YAML).

Happy to create a fork and point to the code I have for easier debugging. Though, I mainly implemented @kylemart's existing work here and just changed some things around to avoid conflicts.