Fix: Improved date parsing for Keyoapp sites

[Nyantad]

Introduced DateSelector variable in Keyoapp base class: This allows individual sites to define a custom CSS selector for the date element. The previous fixed selector (.text-xs) failed to accurately capture the date on sites with different HTML structures, for example, it was capturing a "New" tag instead of the actual date.

Updated ReaperScans and StarboundScans to use specific DateSelector values:
These sites required more precise selectors to pinpoint the correct date element within their unique HTML otherwise, it would capture the "New" tag for recently released chapters.

Simplified parseRelativeDate function: Removed the code that sets the time to midnight because it caused incorrect chapter release times. Now, the function correctly calculates the release time by subtracting the relative time from the current time.
If a chapter was released "3 hours ago" and the current time is 4:00 PM, the old code would incorrectly calculate the release time as 9:00 PM the previous day (midnight minus 3 hours). The new code correctly calculates the release time as 1:00 PM today (4:00 PM minus 3 hours).

Checklist:

• Updated extVersionCode value in build.gradle for individual extensions
• Updated overrideVersionCode or baseVersionCode as needed for all multisrc extensions
• Referenced all related issues in the PR body (e.g. "Closes #xyz")
• Added the isNsfw = true flag in build.gradle when appropriate
• Have not changed source names
• Have explicitly kept the id if a source's name or language were changed
• Have tested the modifications by compiling and running the extension through Android Studio
• Have removed web_hi_res_512.png when adding a new extension

[Nyantad]

Also i fixes relative date parsing, adds French support, and corrects Astral Manga date format.