Add summary table of sites and other site info to docs

[eteq]

The sites functionality in #26 only has API docs - there need to be some narrative docs describing how it's used. @cdeil suggested in #26 that there should be an auto-generated table of the observatories that are built-in (I think just the names/aliases/description/source are sufficient for the docs).

[cdeil]

@jberlanga – Maybe you could address this issue in #42 ?

[eteq]

I agree with @cdeil about the narrative part being in #42, but it will be a bit more complicated to auto-generate a table (that requires adding code to the module itself). So I suggest treating that as a separate PR after #42

[jberlanga]

@cdeil @eteq I'll add a section about the sites (with @bmorris3's input) for now. in PR #42

[bmorris3]

Let me know if/when you need help with the sites docs, @jberlanga.

[jberlanga]

@astropy/astroplan-maintainers -- Apologies for leaving this issue by the wayside! Moving this to 0.2 (unless someone gets to it before 0.1 drops).

[adrn]

I have an idea for how to do this -- if we convert the observatories.json file into a CSV, we can use:
http://docutils.sourceforge.net/docs/ref/rst/directives.html#csv-table

But I want all of the longitudes/latitudes to be numbers so I can easily generate Google maps links for each row in the table...

[bmorris3]

Now that #105 is merged, might you be able to attack this @adrn?

[bmorris3]

Since astropy/astropy#4042, the sites module has been ~ported to astropy, making these docs unnecessary in astroplan (though they'd still be great in astropy). When sites is removed in favor of the astropy implementation, this issue should be closed.