MueLu: bugfix in Level::Request

I'm very sure that the Request function was not fully correct before. Put in
a lots of comments. All nightly tests seem to be fine (including the MultipleSolve test)
MueLu: reenable MultipleSolve test

add a smaller MultipleSolve test which reuses Ptent for solving 3 times
three different scaled Laplace problems.
Support sidesets touching arbitrary blocks in generated meshes.

Needed to unit test CDFEM part decomposition.

(From Sierra)

Build/Test Cases Summary
Enabled Packages: SEACASIoss
Disabled Packages: Panzer,PyTrilinos,SEACASExo2mat,SEACASMat2exo
Enabled all Forward Packages
0) MPI_DEBUG => Skipped configure, build, test due to no enabled packages! => Does not affect push readiness! (-1.00 min)
1) SERIAL_RELEASE => Skipped configure, build, test due to no enabled packages! => Does not affect push readiness! (-1.00 min)
2) MPI_DEBUG_SS => passed: passed=21,notpassed=0 (21.96 min)
3) SERIAL_RELEASE_SS => passed: passed=22,notpassed=0 (23.25 min)
TPetra/Kokkos: more changes to work on Kokkos integration

-CG solve now works both with OpenMP and Threads backend
-CUDA still not working, because of design differences with old Kokkos
-includes some small bugfixes related to Kokkos devices

Christian
MueLu: forgot this file
Intrepid MiniTensor: Minor modifications to strict and strong ellipticity
checks.