aemfvp-a: update documentation for 2024.04.15 release

Update documentation about the changes being introduced in the 2024.04.15
release of the Base AEM-A-RME and AEM-A FVP platform software stack.
Updates include
- added details for UEFI boot of distro debian image on FVP.
- lkvm realm machine supporting UEFI boot of distro debian image on rme
  security state.
- added networking support use case for base fvp.
- Release notes for Q1'24 updates in aemfvp-a-rme and aemfvp-a.
- release detail section added in notes to capture release specific details.
- guide for updating the stock kernel in ubuntu raw disk with cca aware kernel.
- automatable use case for distro's stock kernel update with cca aware kernel
  built with rme stack.

Signed-off-by: nitin sharma <nitin.sharma3@arm.com>
Change-Id: I56fba2835898fb001e8f05262e50d211d71491c9