Add a function to retrieve OS major version number from OS_VERSION_PARAMS

[jouvin]

Currently (24.10.0), OS_VERSION_PARAMS variable (dict) contains a parameter majorversion that was designed to be a string to accomodate any versioning/naming scheme (including names). The problem is that comparison is done across the template library with a string comparison, like >= '9' (for RHEL derivatives) but it will not work with v10 and later... Rather than fixing each comparison by converting the string to a long with the risk of a version string that cannot be converted, the idea is to implement a function like get_os_major_version() that will do what is necessary to return a number.