Support creating SAS for Azure stoage services

1. Support new commands
   * azure storage container sas create
   * azure storage blob sas create
   * azure storage table sas create
   * azure storage queue sas create
2. Fix bugs: some of storage unit tests cannot be run live
  
<!---@tfsbridge:{"tfsId":2307430}-->
This split looks fishy. What does this do ? Split by every letter ? Why not just use an indexed for and avoid the realocation ?