Update DEI working group page and fix Pride spotlight tags

[lparsons]

Description

Updates to the DEI working group page:

• Restructured the page around the working group's current focus areas, each as its own section linked from a "Current Focus" list: Annual Diversity Report (in progress), Education and Promotion of DEI (Mission Statement, Speaker Series, Media Club, and Resources nested here), Equity and Inclusion Challenges, and Celebrating Diversity (Pride Month and Black History Month spotlight links).
• Updated co-chairs to Lance Parsons and Alex Koufos.
• Corrected the meeting cadence (monthly, second Wednesday at 12 PM PT / 3 PM ET).
• Added the #wg-diversity-equity-inclusion Slack channel and the DEI General Interest Form to "Getting involved."
• Marked the Speaker Series and Media Club as occasional.
• Added a feedback invitation in the Equity and Inclusion Challenges section (form, #dei-discussion, or messaging the co-chairs).
• Removed the outdated Spanish translation and RSE mentorship sections.

Also fixed the tags on two Pride Month spotlight posts (pride-month → pride) so they show up on the /tags/#pride page alongside the other Pride posts.

Checklist:

• I have previewed changes locally or with CircleCI (runs when PR is created)
• I have completed any content reviews, such as getting input from relevant working groups. If no, please note this and wait to post the PR to the #website channel until the content has been settled.

This content was authored by a DEI working group co-chair.

When you are ready for a technical review/merge, post the for the link for the PR in the US-RSE Slack (#website) to ask for reviewers.

[lparsons]

@exoticDFT Can you review these changes (feel free to fix anything that seems off)?

[exoticDFT]

One thing, which I don't 100% understand. But for some reason all the links are created such that it moves the page to right below the headers, rather than above, so you can actually see the section you're in. I think in the past, I've had to manually create the header tags, but maybe this is a website wide change that can be made to fix these automatic header tags.