Simplify KRB5 recipe

[uilianries]

Specify library name and version: krb5/1.21.2

@Jihadist Thank you for your effort doing this PR to ConanCenterIndex. As it would many changes, I prefer sending you a PR with the suggestion instead of commenting in the PR conan-io#16074.

Some important point that I observed and changed in your PR:

• Updated to the latest version 1.21.2
• As recipe is not working yet on Windows, neither in MacOS, I removed all support. Let's keep it simple first, then improve later.
• The static library requires extra patch affecting the source code. It's something that should be reported in the upstream first. ConanCenter can not afford maintaining non-official patches. Let's keep the recipe as shared-library for now, so people can consume it without invalid configuration
• The Openssl provided by Conan uses zlib enabled by default, krb5 uses find library instead of searching for modules. I sent a PR to the upstream asking to fix it: Search OpenSSL using pkg-config instead of checking for libraries krb5/krb5#1351
• The test_v1_package is no needed for new recipes. We are avoiding maintaining legacy generators.
• The self.env_info is also no longer supported for new recipes.

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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.

[xakod]

@uilianries thank you for this changes!

• If latest version works it would be great and we should use it. I didn't check build with 1.21.2.
• Ok, I'm agree with you
• Ok
• Thank you again here :)
• Ok
• Nice, I didn't know