doc: Make it easier to report issues in the documentation

- Add extension to get git metadata (date, SHA-1, ...) regarding the
  latest update made to a page
- Add date of last "actual" update to each manually authored doc page
- Add admonition inviting to report issues
- Add button in breadcrumb to report issue

Fixes #60622.

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>