Restructure ecosystem page

[markerikson]

Splits the "Ecosystem" docs page into "Learning Resources" and "Ecosystem", and updates both pages with content from my articles list and addons list.

Fixes #2588 .

[ishankbahl]

Hey @markerikson , should there be a section for recommended boilerplates too?

[markerikson]

@ishankbahl : maybe, maybe not. The general stance of the React and Redux teams is that we don't recommend "boilerplates", especially for learners, because they're generally too complex and full of things that most people don't need.

[ishankbahl]

React docs have a starter kits section under tools.

[markerikson]

Hmm. Don't think I realized that page was there.

Really, though, that page completely works as a list of "Redux starters" too :)

[alexkrolick]

On the topic of this PR:
Separating libraries and learning resources is a good idea 👍

Separately:
The community starter kits (now "Other Starter Kits") section is pretty loosely maintained in the React docs. Dan just did a sweep to clear out some of the ones that don't fit the criteria well, but there isn't a "notability" requirement or anything like that and people add their own all the time. A page like this would almost be better as a wiki or community-upvoted list, since maintainers don't don't vet every addition and the community should feel free to add to it and rearrange it. A task for another day...

Personally I use http://js.coach a lot for finding libraries.

[markerikson]

Since there's been no further comments, I'll merge this in and will hopefully get the docs republished soon.