Alerting: Update provisioning to validate user-defined UID on create (#73793)

* add ValidateUID to util
* provisioning to validate UID on rule creation

---------

Co-authored-by: brendamuir <100768211+brendamuir@users.noreply.github.com>
Co-authored-by: Alexander Weaver <weaver.alex.d@gmail.com>

conf/provisioning/alerting/sample.yaml

@@ -13,7 +13,7 @@ apiVersion: 1
 #     interval: 60s
 #     # <list, required> list of rules that are part of the rule group
 #     rules:
-#       # <string, required> unique identifier for the rule
+#       # <string, required> unique identifier for the rule. Should not exceed 40 symbols. Only letters, numbers, - (hyphen), and _ (underscore) allowed.
 #     - uid: my_id_1
 #       # <string, required> title of the rule, will be displayed in the UI
 #       title: my_first_rule
@@ -82,7 +82,7 @@ apiVersion: 1
 #     # <string, required> name of the contact point
 #     name: cp_1
 #     receivers:
-#       # <string, required> unique identifier for the receiver
+#       # <string, required> unique identifier for the receiver. Should not exceed 40 symbols. Only letters, numbers, - (hyphen), and _ (underscore) allowed.
 #     - uid: first_uid
 #       # <string, required> type of the receiver
 #       type: prometheus-alertmanager