Rewrite BoundaryHistory to support substeps

[wthrowe]

If reviewers prefer, the second and third commits could be moved to a separate PR.

Proposed changes

Upgrade instructions

Code review checklist

• The code is documented and the documentation renders correctly. Run
  make doc to generate the documentation locally into BUILD_DIR/docs/html.
  Then open index.html.
• The code follows the stylistic and code quality guidelines listed in the
  code review guide.
• The PR lists upgrade instructions and is labeled bugfix or
  new feature if appropriate.

Further comments

[kidder]

• I like the rewrite and I have no requested changes.
• clang-tidy has flagged some moves of trivially-copyable type
• gcc11 is not compiling the print function, maybe need a using ::operator<<; or an include in the test?

[wthrowe]

I can reproduce the gcc 11 problem locally, but I'm not having any luck fixing it. Adding using ::operator<<; immediately before the problematic line and including Utilities/StdHelpers.hpp as the first thing in the compilation unit doesn't do anything. Calling operator<< directly either doesn't do anything of gives an error about ambiguity (I think in a different call) depending on exactly how I do it.

[wthrowe]

gcc 11 fixed. Search for print_stl if you want to see how.

[kidder]

Hi @wthrowe some of the clang-tidy errors are ones we have fixed in the past

error: parameter 'entry' is const-qualified in the function declaration; const-qualification of parameters only has an effect in function definitions [readability-avoid-const-params-in-decls,-warnings-as-errors]

[wthrowe]

Disabled some checks in a new commit, fixed the rest. Also deleted an internal function that was never used.

[nilsdeppe]

I confirmed with @kidder that this can get merged