Clean up addons initialization

[nirs]

Addons use too much boilerplate, and do not have good way to pass extra arguments:

This can be cleaned up using an drenv.addon module, similar to drenv.test:

#!/usr/bin/env python3                                                                                                                                                                    

from drenv import addon
from drenv import kubectl

args = addon.init()
addon.info("Deploying recipe crd")
kubectl.apply(
    "--kustomize",
    "https://github.com/RamenDR/recipe.git/config/crd?ref=main&timeout=120s",
    context=args.cluster,
)

addon.init() will:

• change directory
• configure logger
• log start message
• configure sys.excepthook
• configure default addon arguments (cluster, -h, --help)
• configure extra arguments that drenv can use to pass more info to the addon
• parse arguments
• print standard usage message
• print standard --help text
• fail if called more than once

To configure addon specific arguments we can use:

addon.add_argument(...)