Host Mission page on website from community repo

[chalin]

• Current location of the page: https://github.com/open-telemetry/community/blob/main/mission-vision-values.md
• Subtask of Ensure non-API docs are hosted on opentelemetry.io #833

Subtasks:

• Add page to this repo
• Remove page from https://github.com/open-telemetry/community
• Host community pages via repo submodule #1809
• Backport of mission copyedits from website community#1369
• [editorial] Fix Hugo front matter in mission-vision-values.md community#1370
• Mount community mission page #2381

/cc @austinlparker @bhs

[chalin]

@svrnm Thanks for migrating the mission page. Might you be willing to remove the source page from the community repo (see the subtask list above). If you'd prefer that I do it, let me know.

[svrnm]

@chalin created the PR accordingly

[svrnm]

deleted my last comment, it's not fixed per the last comment on the community ticket open-telemetry/community#1056:

Discussed in the GC call. GC recommendation is to use the same publishing mechanism for Community repo that we already use for including Specification into the website pages.