Externals Update and CentOS 7 Fixes, 21.0 branch (2020.09.30.)

This MR is meant to fix all the remaining problems with the x86_64-centos7-gcc62-opt builds of the 21.0 branch. (https://bigpanda.cern.ch/nview/?nightly=21.0_Athena_x86_64-centos7-gcc62-opt)

First off, it updates all projects to atlasexternals-1.0.48.5. It brings the following updates wrt. atlasexternals-1.0.48.4 (atlasexternals@1.0.48.4...1.0.48.5):

• Forced AthenaExternals and AthDerivationExternals not to take UUID from the LCG release, even if it provides it;
  • This was necessary because even though LCG_88 on the x86_64-centos7-gcc62-opt platform provides a version of UUID, the TDAQ projects did not use that in their own builds. So in the offline build we must take UUID from the operating system as well. (Not to mention that LCG_88 seems to take UUID for its Qt4 build from the OS as well. Which showed up as a linking error in the QatPresenterApp package. That was not because of TDAQ.)
• Fixed the build of CLHEP with modern CMake versions.
  • This was only necessary for my own sanity. I did my test builds using the latest version of CMake (3.18.3 at the time of writing). Which did not build the CLHEP package successfully without this fix.

On top of the "UUID fixes" the nightly also has a cryptic build failure coming from FTKStandaloneMonitoring. Which comes from the fact that the package relies on the tdaq project. (Not tdaq-common, but tdaq.) Which was not built for x86_64-centos7-gcc62-opt. And I assume (@rhauser?) that it will not be. So I decided that it was probably just a mistake that this package was left in the Athena project. Since no other package in the project needs tdaq. And I removed it in this MR.

This should conclude ATLINFR-3736 for the 21.0 branch at least...