Fix bugs in FileUploader, BinaryFile_sp_GetByID.sql, and GetFile.
+ StorageEntityTypeId wasn't getting set
+ StoredProc didn't return data if the StorageEntityTypeId wasn't set on BinaryFile.  Fixed it so that it'll get StorageEntityType from BinaryFileType if BinaryFile doesn't have it set
+ Updated StoredProc so that the same SELECT statement can be used for either the Id and Guid cases
+ Fixed bugs in GetFile due to columns getting fetched in the wrong order (and wrong column name)
added new systemguid for BinaryFileType EXTERNAL_FILE
added new Rock:LinkButtonField for the Rock:Grid that can be used like a regular ButtonField but works like our DeleteField and EditField grid fields (it returns the e.RowId, etc)
ExternalFileList block is ready to review. It hasn't been added to a page yet.