Cleanup ART package: remove the software and only keep CMake

Removing ART software from the ART package. Only keeping the ARTEnvironmentConfig.cmake and CMakeLists.txt in the package to add ART input CVMFS directory to the DATAPATH.

The latest version of ART (1.0.7) is available via "lsetup art"

setupATLAS
asetup <nightly>
lsetup art

Adding @emoyse, @wlampl, @akraszna

This merge request affects 1 package:

• Tools/ART

added 21.1 Tools review-pending-level-1 labels

CI Result FAILURE

	AthenaP1
externals
cmake
make
required tests
optional tests

Full details available at NICOS MR-26464-2019-09-10-19-05
AthenaP1: number of compilation errors 0, warnings 162
For experts only: Jenkins output [CI-MERGE-REQUEST 40610]

Same as the other one. Please have a look at the CI result.--MR L1

added review-user-action-required label and removed review-pending-level-1 label

merged

mentioned in commit 25fb7ff2

mentioned in commit be364b33

mentioned in merge request !27575 (closed)

added sweep:ignore label