:bulb: [Feature] Avoid runtime installation of CanarieAPI dependencies

[fmigneault]

Description

To avoid rate-limiting from GitHub/DockerHub requests when retrieving tags and their release times, CanarieAPI uses requests-cache package to limit the amount of requests it performs (basically each time the configs are loaded otherwise).

birdhouse-deploy/birdhouse/config/canarie-api/entrypoint

Lines 8 to 16 in 59baaa7

	pip install requests-cache
	# chain existing cmd
	exec /bin/sh -c "\
	env >> /etc/environment && \
	cron && \
	nginx && \
	gunicorn -b 0.0.0.0:2000 --workers 1 --log-level=DEBUG --timeout 30 -k gevent canarieapi.wsgi \
	"

This is a quick workaround, but runtime installation reduces reproductibility of the obtained image.
However, the package is not itself employed in CanarieAPI in other circumstances, as no caching is actually applied on performed requests by CanarieAPI, since its goal is to retrieve up-to-date statuses of monitored services each time.

A potential fix would be to pin the installed version.

References

• fix CanarieAPI config to support Python 3.x #284 (review)
• fix CanarieAPI config to support Python 3.x #284 (comment)

Concerned Organizations

• all using CanarieAPI