Remove CTL "surrogate scripts" that now live in tracker-surrogates repo

[kzar]

We have recently moved[1] the Click to Load "surrogate scripts" to the tracker-surrogates[2] repository. Let's complete the work by removing the old copy of those files from this repository.

1 - duckduckgo/tracker-surrogates@54933a3
2 - https://github.com/duckduckgo/tracker-surrogates

Reviewer: @jonathanKingston
CC: @ladamski

Steps to test this PR:

1. Ensure CTL integration tests still pass.
2. Install extension.
3. Open developer tools and switch to network panel for a new tab.
4. Navigate to https://privacy-test-pages.glitch.me/privacy-protections/click-to-load/
5. Ensure the Facebook SDK request is redirected to the surrogate script successfully.
6. Ensure the test page works OK.

Automated tests:

• Unit tests
• Integration tests

Reviewer Checklist:

• Ensure the PR solves the problem
• Review every line of code
• Ensure the PR does no harm by testing the changes thoroughly
• Get help if you're uncomfortable with any of the above!
• Determine if there are any quick wins that improve the implementation

PR Author Checklist:

• Get advice or leverage existing code
• Agree on technical approach with reviewer (if the changes are nuanced)
• Ensure that there is a testing strategy (and documented non-automated tests)
• Ensure there is a documented monitoring strategy (if necessary)
• Consider systems implications

[jonathanKingston]

LGTM