* Add feature / amendment "InvariantsV1_1"
* Adds invariant AccountRootsDeletedClean:
* Checks that a deleted account doesn't leave any directly
accessible artifacts behind.
* Always tests, but only changes the transaction result if
featureInvariantsV1_1 is enabled.
* Unit tests.
* Resolves#4638
* [FOLD] Review feedback from @gregtatcam:
* Fix unused variable warning
* Improve Invariant test const correctness
* [FOLD] Review feedback from @mvadari:
* Centralize the account keylet function list, and some optimization
* [FOLD] Some structured binding doesn't work in clang
* [FOLD] Review feedback 2 from @mvadari:
* Clean up and clarify some comments.
* [FOLD] Change InvariantsV1_1 to unsupported
* Will allow multiple PRs to be merged over time using the same amendment.
* fixup! [FOLD] Change InvariantsV1_1 to unsupported
* [FOLD] Update and clarify some comments. No code changes.
* Move CMake directory
* Rearrange sources
* Rewrite includes
* Recompute loops
* Fix merge issue and formatting
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Co-authored-by: Pretty Printer <cpp@ripple.com>
