Enable Libraries v2 (beta) in production

[pomegranited]

Replace the LIBRARY_MODE env flag with two toggles in edx-platform, off by default:

• contentstore.new_studio_mfe.disable_legacy_libraries
• contentstore.new_studio_mfe.disable_new_libraries

Make the Meilisearch tutor plugin a "core plugin" for Sumac, enabled by default.

The deployment of this change needs to be coordinated with edX/2U, as it will affect their production environment.
If 2U doesn't want to deploy Meilisearch yet, they can override it on their deployment as long as we give them heads up.

[bradenmacdonald]

@pomegranited I think we'll need to keep the current three options for the setting; we'll just need to change the default to MIXED. And if 2U doesn't want MIXED yet, they can override it on their deployment as long as we give them heads up.

[pomegranited]

@bradenmacdonald I added the Studio Home update you posted on Slack in here too -- Are we doing that? Who can provide the real text?

[bradenmacdonald]

@jmakowski1123 Please let us know if you want to do the "Libraries BETA" tab label, and/or add some other text ^

[jmakowski1123]

Here's a related ticket outlining the requirements for default configurations: #1334 I created this ticket so we can communicate to BTR for configuring on the sandbox too.

[jmakowski1123]

@jmakowski1123 Please let us know if you want to do the "Libraries BETA" tab label, and/or add some other text ^

Yes, here's a full story: #1336 I hope we can adjust the text later, ie add a url once the docs are written?

[bradenmacdonald]

@jmakowski1123 Yes, I'm sure we can adjust the link later, even after the Sumac cut.

[pomegranited]

Note for 2U/edX: the Authoring MFE will show Libraries V2 only if Meilisearch is running (settings.MEILISEARCH_ENABLED) and contentstore.new_studio_mfe.disable_new_libraries == False. So merging this PR doesn't affect edx.org.