add cache filters for stored within or before last 8h / 24h / 7d / 30d

[moving-bits]

Fixes #7498

add cache filters for "stored within xxx" and their opposite ("stored before xxx") with xxx = any of 8 hours, 24 hours, 7 days, 30 days

[moving-bits]

While looking over this PR I am a bit confused why those strings above have already been included before.
AFAIR there was no filter of such kind in the past, was it?

I created this PR in two steps (two commits): First the positive conditions ("saved within xxx") and strings needed for this, then the negative conditions ("not saved within xxx"). For consistency between the two blocks I had to adjust some strings from the first commit.

[Lineflyer]

Agreed to be revisited by @moving-bits due to better sequence in filter menus / sub menus.

[moving-bits]

Moved the eight new filters together with the two existing filters "Stored" and "Not stored" into its own filter category "stored" (directly below category "status"):

[moving-bits]

Agreed to be revisited by @moving-bits due to better sequence in filter menus / sub menus.

done