Add in all wiki articles from now defunct atom

[confused-Techie]

In this PR I've added all the old Atom wikis.

I had originally moved this into our old documentation under a special wiki only section, but since we've remapped the entire website, I took this chance to instead group things in a more logical way.

Adding the autocomplete-plus data into infrastructure since anyone wanting to write a package for autocomplete+ would likely to expect to find the information there, alongside other documentation about integrating with core features.

Since other wiki articles like ide-java and atom-languageclient detailed information more about maintaining a package, I added those to the maintaining-pulsar section.

Lastly, the github package wiki doesn't do any of those things, but I do find it a cool nugget of history about the project, so also added it to maintaining-pulsar.

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When I originally checked every single package repo (when I originally had forked all of them to Pulsar) these were the ones I identified as having a wiki, so this PR should constitute every single wiki, and entry that exists in the Atom organization. Since I would very much like to make sure we archive this data, it seems rather reasonable to add it here, more-so in the case of helpful documentation like for autocomplete+

[savetheclocktower]

Not sure. I like the idea of preserving this information; I'm not convinced this is where it should live.

The most useful of the Wiki pages is that of autocomplete-plus, and I could see that one going into the docs — perhaps under a new “IDE features” section. The others are less useful:

• The github package's wiki is practically meeting notes (though it is interesting to see some architecture discussion)
• atom-languageclient’s Wiki page is out of date and superseded by this one on the atom-community fork

It's great that we've captured the contents of these pages just in case further culling takes place on GitHub’s part, but I'd prefer not to decide the fate of this content just yet.