Update to 6.8.X + 6.8.X-rtY

This MR consists of the following commits:

• Update to 6.8.X
• d/copyright: Exclude 'action-ebpf' as that's a binary blob
• d/installer/modules: Remove modules removed from upstream kernel
• d/config: Update with the help of kconfigeditor2
• [rt] Update to 6.8.2-rt11 or later
• [Optional rt adjustments for later upstream versions]

---

This MR had the following lintian error:
E: linux source: source-is-missing [tools/testing/selftests/tc-testing/action-ebpf]

It is caused by the following commit: https://git.kernel.org/linus/a79d8ba734bdbd2574ad16dd1b96506e5f642c4a
commit message:

selftests: tc-testing: remove buildebpf plugin

As tdc only tests loading/deleting and anything more complicated is
better left to the ebpf test suite, provide a pre-compiled version of
'action.c' and don't bother compiling it in kselftests or on the fly
at all.

This is now fixed by adding that file to debian/copyright's Files-Excluded section.