feat(Show Originals): Allow filtering blog search/tagged/filtered-by-type

[marcustyphoon]

Description

Currently, Show Originals has no effect if you search or filter a specific blog's posts in Peepr. This allows one to enable Show Originals in this case.

Internally, a separate peeprFiltered location is added to the code, as I don't think it makes sense to apply the remembered mode for viewing a specific blog when searching. This mode always defaults to off and is never remembered. The location is defined as "any peepr timeline that's not the main peepr posts view" so that exhaustive timeline id utils for the various options aren't necessary.

Somewhat related to, merge conflicts with, and is probably about as niche as #1378. (By which I mean I want both of them, but who knows if anyone else does.)

Testing steps

Open a blog in peepr and turn Show Originals on on said blog.

Confirm that Show Originals shows a default-off but functional control element on that blog when:

• filtering by post type (nothing in search bar)
• searching for something
• searching for something and [filtering by post type or not, filtering by original posts or not, and viewing top posts first or not]; all 8 combinations should work
• viewing posts with a certain tag
• viewing posts with a certain tag and filtering by post type

Clear the search and confirm that Show Originals goes back to being on, as it remembered your preference for viewing blogs in peepr with no filter.

Add the blog in question to the "always show posts from these blogs" list and confirm that Show Originals appears disabled both with and without a filter.

[marcustyphoon]

Related: #1985.

[marcustyphoon]

I don't remember this PR well; I'll have to look back into it. Anyway, I assume that because I made it as nondraft it should be fully functional, but as it doesn't have a description written it should be draft.