[linter] Add first rule for test_package files

[jgsogo]

Rules for recipe conanfile.py and for test_package/conanfile.py should be different. Here I'm introducing the first difference (easy one):

• recipe files require a name attribute
• that name attribute is forbidden in test-package ones

This should serve as a starting point to add more rules.

[conan-center-bot]

Changes not allowed in build 1:

[linter/check_no_test_package_name.py, linter/conanv2_test_transition.py, linter/conanv2_transition.py, linter/pylintrc_testpackage, recipes/aaf/all/test_package/conanfile.py]

Split them in several pull requests if you are making changes in more than one folder..

[jgsogo]

💚

[uilianries]

Nice!