Prefix URL Rewrite

[sarahalsmiller]

Changes proposed in this PR:

• Implement support for URLRewrite type filter.

How I've tested this PR:

• Spun up test cluster and configured routes with the URLRewrite filter set

        urlRewrite:
          path:
            type: "ReplacePrefixMatch"
            replacePrefixMatch: "/test"

• Added tests

How I expect reviewers to test this PR:

• Tests passing

Checklist:

• Tests added
• CHANGELOG entry added

  Run make changelog-entry for guidance in authoring a changelog entry, and
  commit the resulting file, which should have a name matching your PR number.
  Entries should use imperative present tense (e.g. Add support for...)

[nathancoleman]

We should add the various kinds of URL rewrites to dev/docs/supported-features.md and check off the one supported in this PR

[manobi]

@sarahalsmiller I would love to test it, in which release is it going to be available?

[Jeff-Apple]

@manobi

This feature will be in version 0.4, which we plan to release next month (August).