Standardize Rewriter::rewriteViaMethod call (#7119)

Standardize Rewriter::rewriteViaMethod call (#7119)

This moves the standard method for rewrites in proofs from TheoryBuiltinProofRuleChecker to Rewriter.  The motivation for this change is to make various kinds of rewrite methods (standard rewrite, extended rewrite, extended equality rewrite, evaluate) accessible throughout the code in a standard way.  After this PR, it is possible to know variants of the REWRITE proof rule application by having access to the rewriter, instead of having to get the builtin proof rule checker.  Note that TheoryBuiltinProofRuleChecker::applyRewrite *cannot* be static since access to the rewriter is not longer permitted to be static.

It also removes some unused infrastructure from Rewriter.

Followup PRs will remove applyRewrite for TheoryBuiltinProofRuleChecker in favor of calling the rewriter directly.