Adding various platforms used by agl

Adding various platforms used by agl

Adding the list of platforms AGL uses for different purposes.

Bug-AGL: [SPEC-4470]
Signed-off-by: Vinod Ahuja <vahuja@unomaha.edu>
Change-Id: I064d8219e13595cf6a28e8e053f835a2e98f0b2e
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/documentation/+/28064
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/documentation/+/28131