CI: move scl loading to before_script

13 jobs for ci_eudaq2 in 8 minutes and 16 seconds (queued for 1 second)
Name Stage Failure
failed
tst:telescope Testing
0% tests passed, 2 tests failed out of 2

Total Test time (real) = 84.23 sec

The following tests FAILED:
1 - test_timepix3tel_dut150um_ebeam120_sim.conf (Failed)
2 - test_timepix3tel_ebeam120.conf (Failed)
Errors while running CTest
ERROR: Job failed: exit code 1