Rework hierarchy_driver and add timer

[Rombur]

This PR reworks hierarchy_driver so that it can be used for profiling. Also add a few timers for some crude profiling.

[codecov-io]

Codecov Report

Merging #170 into master will decrease coverage by 2.47%. The diff coverage is 36.17%.

@@            Coverage Diff             @@
##           master     #170      +/-   ##
==========================================
- Coverage   89.86%   87.38%   -2.48%     
==========================================
  Files          53       53              
  Lines        2724     2823      +99     
==========================================
+ Hits         2448     2467      +19     
- Misses        276      356      +80

Impacted Files	Coverage Δ
tests/hierarchy_driver.cc	45.06% <21.42%> (-50.33%)	:arrow_down:
include/mfmg/common/hierarchy.hpp	74.21% <93.1%> (+4.31%)	:arrow_up:
include/mfmg/dealii/amge_host.templates.hpp	92.35% <0%> (-0.1%)	:arrow_down:
tests/laplace.hpp	96.11% <0%> (ø)	:arrow_up:
tests/laplace_matrix_free.hpp	97.16% <0%> (ø)	:arrow_up:
include/mfmg/common/amge.templates.hpp	88.08% <0%> (+0.27%)	:arrow_up:
tests/test_hierarchy.cc	86.26% <0%> (+0.29%)	:arrow_up:
source/dealii/dealii_hierarchy_helpers.cc	100% <0%> (+0.93%)	:arrow_up:
...rce/dealii/dealii_matrix_free_hierarchy_helpers.cc	100% <0%> (+0.96%)	:arrow_up:
... and 1 more

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[Rombur]

ping

[Rombur]

Can we merge this PR or do you want more changes?

[dalg24]

Fine by me