Add remote_data on all tests that require network

[sergiopasra]

This PR implements a first step towards the goal of running the tests of astroplan without network access. I'm using the decorator @pytest.mark.remote_data from the package pytest-remotedata, which is currently in the dependencies. In the long term, I would like to check one by one the marked tests and see if the network access is actually required or if it is an
accident, typically by using Observer.at_site

[bmorris3]

Neat, thanks! We used to prevent problems due to internet access this with mocks like this:

astroplan/docs/conf.py

Lines 159 to 160 in 7880daa

	#from astroplan.utils import _mock_remote_data
	#_mock_remote_data()

Could you add the --remote-data flag to the test matrix, e.g. here:

astroplan/tox.ini

Line 76 in f1bd503

cov: pytest --pyargs astroplan {toxinidir}/docs --cov astroplan --cov-config={toxinidir}/setup.cfg {posargs}

[sergiopasra]

I have added a factor -remote that enables remote data in all tests. The tests without -remote use only local data. If you prefer that -cov tests are run always with remote data, it can be done also.

[pllim]

Why is subaru needed here at all? 🤔

[sergiopasra]

It's true, that variable is not used

[pllim]

Problem with marking lines with remote data, you also need to mark all the subsequent lines derived from here onwards.

[sergiopasra]

Yes, there are some tests where I should mark also the next line

[sergiopasra]

I have also noticed that I was using REMOTE_DATA in some tests that don't need it. I have removed them

[pllim]

Thank you very much for smoking out the remote data tests, @sergiopasra ! I took some liberty to push follow up commits here. Hope you don't mind.