Add Vendor Code and name in FBL3N report

To add Vendor Code and name in FBL3N report use BTE concept. 

• Append structure in RFPOS & RFPOSX. 
• In SE38 to regenerate the program RFPOSXEXTEN. 
• Create a new function module ZXXXX and assign it to BTE 00001650.
• In the FM select the vendor code from BSIK or BSAK by Document no.