[CI] Fix Jenkins pipeline for testing hooks

[danimtb]

From PR #525 we realized that the pipeline was getting stuck due to macos machines not available. I thought this was an easy fix but it required to almost completely redo the whole pipeline.

Here is the summary of tasks covered in this PR:

• Remove tox usage: It was causing a lot of installation problems and delays in the CI (windows machines even got stuck executing tox).
• Remove Python script to get the latest version of Conan: It was causing some trouble getting the latest Conan v2 instead of the latest v1. Now this is done via pip install.
• Update the Macos agent label to use the new Macos M2 machine.
• Fix some requirement versions creating conflicts.
• Add Conan v2 test for the "reduce conandata" hook.
• Added environments to test with both conan v1 and v2 in develop/develop2, latest and prev (latest -1) versions.
• Continue to test hooks with different Python versions (this might look like an overkill but decided to keep it for the moment and avoid any kind of regression).
• Add script to launch tests in Windows.
• Keep hook_conan-center-v2 hook untested for now.

Testing on Windows is slower than in other environments, that's why I decided to reduce the Python versions tested on this platform. The last stage in Linux is the complete one with all the combinations: python versions conanv1/v2 conan versions (develop, latest, prev).

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For future PRs:

• Agree on the Python versions to run tests (align here with the Conan client and its CI)
• Add conanv1prev and conanv2prev versions as global variables in the Jenkinsfile for easy updates (these would be the only things to update in the CI whenever there are new releases).

[uilianries]

Yes, from time to time, the CI gets wild in hooks.