CLI to insert resource into local catalog

[Pierlou]

This proved useful locally for me, to insert a new resource into my local catalog (or update an existing one), instead of having to do database shenaningans

[bolinocroustibat]

Quite useful indeed, thanks!
LGTM, but should we write a test for this new command in tests/test_cli.py?

[Pierlou]

I don't like the "default" value in the CLI function, but it seemed to be the only way to make the test pass. We will fix this when #232 is treated

[bolinocroustibat]

Don't forget the changelog!