7.10.0 Release/publish actions: Add Chrome web store automation

[marcustyphoon]

Uses chrome-webstore-upload-cli to automate uploading releases to the Chrome web store and renames the release metadata action for clarity.

Should match the documentation in #2163.

[hobinjk]

Overall seems reasonable but I think there's a typo

[marcustyphoon]

Okay, I think I'm done poking at 7.10.0 if we want to go forward with releasing it. I retested upgrade installs on Firefox 102 and Chrome 105.

Note that:

• This PR's code isn't tested (besides not having an extension of my own to test the Chrome web store with, I of course don't know if the referenced secrets are correct; we'll find out the first time this is run.) To try to interrupt my pattern of merging broken stuff and then leaving master in a broken state until more PRs can be reviewed, I think it probably makes sense to merge this when we want to go forward on the release so we can see if it works/fix it if it doesn't, and for another maintainer with access to the secrets and the extension stores to do the merge and action run or be around when doing so. (Who does actually have access to the extension store accounts? Is it just @hobinjk? Obviously I'm saying this as though I could be referring to anyone else as kind of a joke, but I'm kind of curious about the answer regardless.)
• Maybe it makes sense to make even more actions that just do the Firefox part and just do the Chrome part? It would make troubleshooting easier if (when) these don't work as written and the actions have to be retried. We have a lot of actions, though, which is already confusing; once these work reliably I think it makes sense to have as few as possible. They are sort of convenience features, anyway, in that the extension was deployable without them (just not by me).