doc: first fully generated json rpc markdown

next patch will have the schema and generation python script

Change-Id: I333c01e35fb295e04a1be75b6965994f1fe00ca2
Signed-off-by: Boris Glimcher <Boris.Glimcher@emc.com>
Reviewed-on: https://review.spdk.io/c/spdk/spdk/+/26089


Reviewed-by: Tomasz Zawadzki <tomasz@tzawadzki.com>
Tested-by: SPDK Automated Test System <spdkbot@gmail.com>
Reviewed-by: Konrad Sztyber <ksztyber@nvidia.com>