Revert examples to heroku-18 since nothing works on heroku-24

[ianheggie-oaf]

Relevant issue(s)

• Update example scrapers to use heroku-24 buildstep platform and either get them working or remove them from the published list of supported languages #1443 - work on examples in this and its sub issues
• Enable the heroku-24 buildstep platform so we can resolve multiple nokogiri vulnerabilities #1440 - morph was updated but all exampls fail on heroku-24

What does this do?

Revert the morph documentation examples to code that works on heroku-18 (aside from python which doesn't work on anything)

Includes:

• Re-enabled php and perl languages for testing and continue to work on heroku-18 HOTFIX #1455

Why was this needed?

The example scrapers work in the docker runner specs on my machine, but not on morph.io itself. This was discovered when I updated my example_*_scraper repos and ran them.

Implementation/Deploy Steps (Optional)

capistrano deploy

Notes to reviewer (Optional)