Speedup install dependencies

[overengineer]

Reduced time of install_requirements on startup from about ~12 seconds to ~7 seconds by using pip options.

[JR-Morgan]

LGTM!

Cheers!

[overengineer]

@JR-Morgan Can we skip dependency checks entirely if the addon is already installed?

[JR-Morgan]

Potentially yes.
I think the best way for us to do this is, after installing the dependencies successfully, let's delete the requirements.txt file.
and update our dependency installation to check for the existence of the requirements.txt

This way, we only run pip once (assuming it was successful).
and this should handle updating the plugin too (I.e new versions of our connector with a bundled requirements.txt).