add KMP search algorithm (gated by build flag)

[midzer]

Description

KMP search algorithm by feature discussion in #880

Should fix #1229

Types of changes

• Chore (tooling change or documentation change)
• Refactor (non-breaking change which maintains existing functionality)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• My code follows the code style of this project.
• I have added new tests for the bug I fixed/the new feature I added.
• I have modified existing tests for the bug I fixed/the new feature I added.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[midzer]

Note: this PR has not been tested yet, as npm watch environment threw other, unrelated errors in the browser dev console. Also, tests and linter has not been run.

[Xon]

@midzer you can ignore those e2e test failures, but the unit tests probably need a bit more work and eslint run on the code to match the rest of the code base.

[Xon]

I've setup a new v12 branch for new feature work, once that is done it can get merged into main

[Xon]

I've fixed the issue with the search flags, and will merge that into the next version update (v11.1.0 as this can be done without breaking backwards compatibility)

The base branch was changed.