Update experimental models to build with new tolerance settings

[pelesh]

Description

Update experimental power flow models and related examples to build with the new method for setting tolerances.

Proposed changes

Add method setAbsoluteTolerance(RealT) to component models Generator2, Generator4Governor, and Generator4Param.

Update related examples to set solver tolerances and max number of steps as:

  idas.setTolerance(1e-7, 1e-9);
  idas.setMaxSteps(2000);

Checklist

• [N/A] All tests pass.
• Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
• The new code follows GridKit™ style guidelines.
• There are unit tests for the new code.
• The new code is documented.
• The feature branch is rebased with respect to the target branch.
• [N/A] I have updated CHANGELOG.md to reflect the changes in this PR. If this is a minor PR that is part of a larger fix already included in the file, state so.

Further comments

Experimental examples are not expected to run successfully. This PR will just enable building these examples correctly in the target branch. For these examples to run correctly issue in SUNDIALS needs to be addressed.

[Steven-Roberts]

I think the failing tests should be fixed by these changes made in v1 of this branch
6988fd6
2918c52