chore: Update CVMFS/LCG setup scripts

[paulgessinger]

Removes LCG97 and 98 setup scripts in favor of 100 & 101.
Also updates the scripts to run on CentOS Stream 8

[codecov]

Codecov Report

Merging #1314 (ddf93f3) into main (55b8ce6) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1314   +/-   ##
=======================================
  Coverage   47.45%   47.45%           
=======================================
  Files         375      375           
  Lines       19778    19778           
  Branches     9273     9273           
=======================================
  Hits         9385     9385           
  Misses       4010     4010           
  Partials     6383     6383           

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[Corentin-Allaire]

Looks good ! If I understand correctly this mean that we won't be testing acts with gcc9 any more right ?

[paulgessinger]

I'm not dropping any versions from CI in this PR. In the CI we we're already on LCG100 and LCG101. The ubuntu 20.04 build still runs gcc9 I think, though.