Updated links to latest available L1 documentation
Removal of unneeded environment variable in aerial_l1_entrypoint.sh
Removal of unneeded checkout command from doc
Reword Aerial Entrypoint script paragraph to separate in multiple sentences
New UE has been tested with Aerial setup
Change bash blocks to reflect that cuBB container no longer uses root
Add alternative instructions to obtain nvipc sources from container
Add note in Prepare the L1 image section specifying default config file and location

Co-Authored by: Reem Bahsoun <reem.bahsoun@openairinterface.org>