Local Execution

[reyna-abhyankar]

Description of changes:

Implement local execution

Related Issues:

Linked Issues:

• Issue #

Issues closed by this PR:

• Closes #1051
• Closes #1282
• Closes #1043
• Closes #1044
• Closes #924

Initial TODO

• [x] allocator
• [ ] local backing
  • [x] constructor
  • [ ] init
  • [x] forward
  • [x] backward
  • [ ] update - refactor optimizer
  • [x] local task argument accessor
• [x] port over code from #1097
• [ ] reorganize repo to be able to build operators, kernels, and local execution without legion
• [ ] new plantuml diagram that matches the interface

Later TODO

• [ ] make signatures, invocations, bindings, etc. all immutable data types and construct them with a OpTaskSignatureBuilder etc.

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This change is