First iteration of AIMS2 updated docs

Basically this new doc reviews some outdated sections, such as those referring to Authorization, databases, TFTP structure, and adds resources that were not tracked anywhere. Some of the docs referred to certain configurations not relevant any more or that are different as of today.

I took the opportunity to update the tbag secrets for aims hostgroup. I did not yet delete them from linuxsupport/lxsoft just in case you know about anything that might be using these secrets.