libcurl: add GitHub mirror & prefer .tar.xz

[SpaceIm]

closes #20154

I've also changed from .tar.gz to .tar.xz since archives are smaller.

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• I've read the contributing guidelines.
• I've used a recent Conan client version close to the currently deployed.
• I've tried at least one configuration locally with the conan-center hook activated.

[github-actions]

🤖 Beep Boop! This pull request is making changes to 'recipes/libcurl//'.

👋 @Hopobcn you might be interested. 😉

[ghost]

I detected other pull requests that are modifying libcurl/all recipe:

• libcurl: add version 8.4.0 (fix CVE-2023-38545) #19769

This message is automatically generated by https://github.com/ericLemanissier/conan-center-conflicting-prs so don't hesitate to report issues/improvements there.

[AbrilRBS]

Thanks a lot! The changes look good for me, and I think changing the format makes sense in this case now that we're adding them

[AbrilRBS]

Retriggering when the CI queue clears a little :)

[conan-center-bot]

Conan v1 pipeline ✔️

All green in build 4 (2a640f410991513a2086c995c0231933e9824c9c):

• libcurl/8.2.1:
  All packages built successfully! (All logs)

• libcurl/8.2.0:
  All packages built successfully! (All logs)

• libcurl/7.78.0:
  All packages built successfully! (All logs)

• libcurl/7.84.0:
  All packages built successfully! (All logs)

• libcurl/7.87.0:
  All packages built successfully! (All logs)

• libcurl/8.1.2:
  All packages built successfully! (All logs)

• libcurl/7.79.1:
  All packages built successfully! (All logs)

• libcurl/7.86.0:
  All packages built successfully! (All logs)

• libcurl/7.88.1:
  All packages built successfully! (All logs)

• libcurl/7.80.0:
  All packages built successfully! (All logs)

• libcurl/8.1.1:
  All packages built successfully! (All logs)

• libcurl/8.0.1:
  All packages built successfully! (All logs)

• libcurl/7.85.0:
  All packages built successfully! (All logs)

• libcurl/7.82.0:
  All packages built successfully! (All logs)

• libcurl/7.83.1:
  All packages built successfully! (All logs)

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Conan v2 pipeline ✔️

Note: Conan v2 builds are now mandatory. Please read our discussion about it.

All green in build 4 (2a640f410991513a2086c995c0231933e9824c9c):

• libcurl/8.2.1:
  All packages built successfully! (All logs)

• libcurl/8.1.2:
  All packages built successfully! (All logs)

• libcurl/8.2.0:
  All packages built successfully! (All logs)

• libcurl/7.83.1:
  All packages built successfully! (All logs)

• libcurl/7.88.1:
  All packages built successfully! (All logs)

• libcurl/7.87.0:
  All packages built successfully! (All logs)

• libcurl/7.84.0:
  All packages built successfully! (All logs)

• libcurl/7.79.1:
  All packages built successfully! (All logs)

• libcurl/7.82.0:
  All packages built successfully! (All logs)

• libcurl/7.85.0:
  All packages built successfully! (All logs)

• libcurl/8.0.1:
  All packages built successfully! (All logs)

• libcurl/7.86.0:
  All packages built successfully! (All logs)

• libcurl/8.1.1:
  All packages built successfully! (All logs)

• libcurl/7.80.0:
  All packages built successfully! (All logs)

• libcurl/7.78.0:
  All packages built successfully! (All logs)