Update latest kernel check with OVERRIDABLE results

There's a logic error in the IsLoadedKernelLatest Action. There're three Action results of the ERROR level but in fact all of them are overridable because setting the CONVERT2RHEL_SKIP_KERNEL_CURRENCY_CHECK variable makes the whole Action to skip.

Acceptance criteria:

• The INVALID_KERNEL_PACKAGE Action result is changed from level ERROR to WARNING - the detected problem is not really about having an invalid kernel package.
  • It's either due to non-matching package names. And having a different package name is practically impossible because of the code

    # append the package name to loaded_kernel and latest_kernel so they can be properly processed by
    # compare_package_versions()
    latest_kernel_pkg = "%s-%s" % (package_to_check, latest_kernel)
    loaded_kernel_pkg = "%s-%s" % (package_to_check, loaded_kernel)
    

• • Or it's due to the compared kernel packages having a different architectures - it means that the system has for some reason incorrectly defined repositories for another architecture.
  • The diagnosis is updated saying that there's an arch mismatch likely due to incorrectly defined repositories on the system.
• The result level of INVALID_KERNEL_VERSION and KERNEL_CURRENCY_CHECK_FAIL is changed from ERROR to OVERRIDABLE because using the CONVERT2RHEL_SKIP_KERNEL_CURRENCY_CHECK envvar essentialy skips the Action altogether.
• The remediation section of the INVALID_KERNEL_VERSION and KERNEL_CURRENCY_CHECK_FAIL results mentions that one can use the CONVERT2RHEL_SKIP_KERNEL_CURRENCY_CHECK envvar to skip the check.

Note:

The INVALID_KERNEL_VERSION could theoretically be kept of level ERROR but then we would need to remove the CONVERT2RHEL_SKIP_KERNEL_CURRENCY_CHECK envvar and replace it with a new envvar for each of the OVERRIDABLE results. But generally converting with an older version of kernel is not expected to cause a conversion failure, so it might be overridable.