Add Tutorials page and DT Concept doc

[sarina]

This new documentation landing page will be linked to from the new openedx.org site footer and is meant as a wayfinding guide for people looking to get up and going (not just quickstarts but demo sites & training links). I'm open to finding a new home for this later on but currently we just need to move ahead with something.

• Add OEX Tutorials community landing page
• Remove Email Announcements page (outdated)
• Add Design Tokens concept doc

Draft docs

• https://docs.google.com/document/d/1GR1ZeD3lL5TiHQQhZV0nCmBjCFO8PvQPlQYUjm4ofhQ/edit?tab=t.0
• https://gist.github.com/brian-smith-tcril/2a6c48a865b1111b9be031043cb1ee5e

Rendered docs

• https://docsopenedxorg--1409.org.readthedocs.build/en/1409/community/references/tutorials.html
• https://docsopenedxorg--1409.org.readthedocs.build/en/1409/developers/concepts/design_tokens.html

[crathbun428]

LGTM - just had one question:

Do we expect a link on the design tokens bullet point on the Tutorials Community Landing page (see screenshot)? Or no? OR is the link going to appear once the design tokens concept doc has been approved?

The rest looks good to me.

[sarina]

@crathbun428 yes, I pushed a change to add it but the build is failing, I will look into it.

[sarina]

@crathbun428 fixed

@brian-smith-tcril - we'd like to merge this by end of day tomorrow, if you could just give a once-over on https://docsopenedxorg--1409.org.readthedocs.build/en/1409/developers/concepts/design_tokens.html (as we discussed in 1-1, it's just pulling the first two sections + the resources section from https://gist.github.com/brian-smith-tcril/2a6c48a865b1111b9be031043cb1ee5e)

[sarina]

@brian-smith-tcril since you're out today I'm going to go ahead and merge this; we can make further corrections in a follow up PR. Feel free to just add comments on this one and I'll do the follow up.