Add StringToLongConverter for automatic handling of long values (#12225)

Backported from master

Change-Id: Ibb91d28aab3731486c84d09547c7af641f39610a
Merge: no
No-op merge from origin/7.1

fbf069d Add StringToLongConverter for automatic handling of long values (#12225)

Change-Id: If8d4e811da5b70774d9d8dc7d82ccd8bc85f8d46