Issues #562,#561,#560:

- No source of entropy in _get_nearest_mirrors_by_network_data()
- _get_nearest_mirrors_by_network_data() fails to exclude near-by private mirrors for extra options.
- Exclude the private mirrors from the mirrors list in the case of fallback behavior

- The Azure mirrors have allowed list of arches
- Decrease level of logging messages in some cases
- Cache subnets of Azure/AWS cloud

utils.py

@@ -39,6 +39,8 @@
 WHITELIST_MIRRORS = (
     'repo.almalinux.org',
 )
+# FIXME: Temporary solution
+# https://github.com/AlmaLinux/mirrors/issues/572
 WHITELIST_MIRRORS_PER_ARCH_REPO = {
     'eastus.azure.repo.almalinux.org': {
         'arches': [