[frogend] (Mastodon) domain block CSV import

[f0x52]

Description

Adds CSV import and export to the bulk import/export interface, tested to be compatible with Mastodon too (glitch-soc).
Generally cleans up the code structure around it a bit too, both on the page itself and the exportType based branching in query.

Also added some information text about the page, and a table comparing the different export formats. Still not sure how well it fits there, might just have to move that to the docs, or a separate page?

Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: [ ] -> [x]

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

• I/we have read the GoToSocial contribution guidelines.
• I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
• I/we have performed a self-review of added code.
• I/we have written code that is legible and maintainable by others.
• I/we have commented the added code, particularly in hard-to-understand areas.
• I/we have made any necessary changes to documentation.
• I/we have added tests that cover new code.
• I/we have run tests and they pass locally with the changes.
• I/we have run go fmt ./... and golangci-lint run.

[tsmethurst]

This looks really good to me :) Just wondering about what we discussed briefly in matrix: domains that are wildcarded by starting with *.. Should we trim that off before it gets sent to gts, or should the server do it?

[f0x52]

hmm I feel like the server should reject them if it doesn't handle it for you, because as a literal * it's never a valid domain. If we don't want to handle them in the backend I can update the client validation to match, and possibly add the trimming there

I'm actually not sure if Mastodon even handles those wildcards either..

[tsmethurst]

I can add something to trim it in the server side, then it'll work via the API too and not just the settings panel: I needed a small thing to work on this afternoon anyway :)

[tsmethurst]

This looks good to me so far :)