Ability to mass select elements in moderation tools

[TheSmilingPony]

Very often, problematic users will manage to spam hundreds of comments, vandalize a tag across hundreds of images, or vandalize many tags on a single image. While there is a staff tool to revert changes in bulk, this tool requires selecting every single instance on a page before submitting.

This request is for the ability to mass select comments and tags in staff tool pages where such things are selectable.

1. Not have to delete comments in comment history pages one by one
2. Being able to "select all" on a tag history page