Replace old Cairo 0.x samples with Cairo 2.6.x ones

[mkaput]

Description

The samples in this repository are written in now-abandoned Cairo 0.x. Cairo 1.0 was a complete redoing of the language, and old code is completely incompatible with it.

This PR removes them and adds new ones that are written in current Cairo 2.6.4. These samples were taken from real repositories: one is an excerpt from the Cairo standard library, and two are listings from the Cairo Book. I have added source and license attributions in comments.

Note that we have recently created an official tree sitter grammar for Cairo. We are also planning to make a TextMate grammar to use in our VSCode extension (https://github.com/starkware-libs/cairo/issues/5776), so I will wait for it to happen, and I'll open a separate PR here that will update the grammar.

Checklist:

• [ ] I am adding a new extension to a language.

  • [ ] The new extension is used in hundreds of repositories on GitHub.com
  • Search results for each extension:
    • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.FOOBAR+KEYWORDS
  • [ ] I have included a real-world usage sample for all extensions added in this PR:
  • Sample source(s):
    • [URL to each sample source, if applicable]
  • Sample license(s):
  • [ ] I have included a change to the heuristics to distinguish my language from others using the same extension.

• [ ] I am adding a new language.

  • [ ] The extension of the new language is used in hundreds of repositories on GitHub.com.
  • Search results for each extension:
    • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.FOOBAR+KEYWORDS
  • [ ] I have included a real-world usage sample for all extensions added in this PR:
  • Sample source(s):
    • [URL to each sample source, if applicable]
  • Sample license(s):
  • [ ] I have included a syntax highlighting grammar: [URL to grammar repo]
  • [ ] I have added a color
  • Hex value: #RRGGBB
  • Rationale:
  • [ ] I have updated the heuristics to distinguish my language from others using the same extension.

• [ ] I am fixing a misclassified language

  • [ ] I have included a new sample for the misclassified language:
  • Sample source(s):
    • [URL to each sample source, if applicable]
  • Sample license(s):
  • [ ] I have included a change to the heuristics to distinguish my language from others using the same extension.

• [ ] I am changing the source of a syntax highlighting grammar

  • Old: [URL to grammar repo]
  • New: [URL to grammar repo]

• [ ] I am updating a grammar submodule

• [ ] I am adding new or changing current functionality

  • [ ] I have added or updated the tests for the new or changed functionality.

• [ ] I am changing the color associated with a language

  • [ ] I have obtained agreement from the wider language community on this color change.
  • [URL to public discussion]
  • [Optional: URL to official branding guidelines for the language]

[lildude]

If the language is completely different and incompatible and the grammar doesn't support both versions of the language, a new language entry should be created and grouped with the old.

Closing as we never remove a language or their valid at the time samples as old code always exists.

[mkaput]

Ok, I'll submit these samples together with the new grammar.