Add new EFP updates page with info about RecordRTC/Pipe

[becky-gilbert]

Fixes #323

You can see a mostly formatted version of the new page here: https://github.com/lookit/lookit-docs/blob/add-efp-updates-recordrtc/docs/source/researchers-runner-releases.rst

There are some values in the new doc page that I will need to add in after the EFP RecordRTC version is actually released. These are written with placeholders like [DATE], [COMMIT SHA] etc.

[becky-gilbert]

@ianchandlercampbell when we're going through your local docs set up, I can show you how to pull this branch down and build the docs locally so that you can see what my changes will actually look like on the docs site. (The Github-formatted version here is better than viewing it in plain text, but is missing the formatting for things like section headers, internal links, and call-out boxes).

[becky-gilbert]

@ianchandlercampbell after merging your edits, I did the following:

• added a Handbrake (GUI) section for converting webm to mp4 format
• made a few very minor copy/formatting edits
• added an entry for the separate (minor) experiment runner release I made today (and updated the commit SHA for the last Pipe version)

I think this is now ready to go! If you want to review the final version, you can see the Github-formatted version here. Or in your local docs repository, you can update your local branch with my changes:

git pull origin add-efp-updates-recordrtc

and then build the docs from inside the docs subfolder:

cd docs
.\make html

Assuming you don't want any further changes, then tomorrow I will:

• release RecordRTC
• grab the commit SHA that's generated from the release and add it where referenced in the docs
• release these docs changes
• make the RecordRTC announcement on slack, and include a link to the docs

[ianchandlercampbell]

@becky-gilbert That sounds like a great plan! I've added one extra commit to fix a copyediting error that I'm pretty sure I introduced with my last round of edits, but otherwise everything looks good on my end. Excited to get this out!