Refactor Auto-Scheduler #3

[SamArch27]

This PR introduces a SIPGraph data structure which simplifies the auto-scheduling process.

This PR resolves issue #2248.

[codecov]

Codecov Report

Merging #2290 (b67ec5f) into master (1f7f0ab) will increase coverage by 0.11%.
The diff coverage is 82.32%.

@@            Coverage Diff             @@
##           master    #2290      +/-   ##
==========================================
+ Coverage   77.29%   77.41%   +0.11%     
==========================================
  Files         458      461       +3     
  Lines       29102    28994     -108     
==========================================
- Hits        22495    22446      -49     
+ Misses       6607     6548      -59     

Impacted Files	Coverage Δ
src/ast/utility/BindingStore.cpp	100.00% <ø> (ø)
src/ast2ram/utility/SipsMetric.h	30.00% <ø> (ø)
src/synthesiser/Synthesiser.cpp	83.83% <0.00%> (ø)
src/ast2ram/utility/SipsMetric.cpp	55.55% <78.57%> (+1.84%)	⬆️
src/ast2ram/utility/SipGraph.cpp	79.33% <79.33%> (ø)
src/include/souffle/utility/SubsetCache.h	88.23% <88.23%> (ø)
src/ast/analysis/JoinSize.cpp	77.51% <91.89%> (+2.08%)	⬆️
src/ast/analysis/JoinSize.h	100.00% <100.00%> (ø)
src/ast2ram/utility/SipGraph.h	100.00% <100.00%> (ø)
src/interpreter/Engine.cpp	84.08% <100.00%> (ø)
... and 4 more

[b-scholz]

Thanks for the refactoring!