create RFC DUBP V12

• rename DUP -> DUBP
• Indicates the possibility of invalid signatures in v10 and v11
• Remove rule BR_G106
• Update rule BR_G102: Obtaining the REF_BLOCK by number only (removal of the constraint on hash)
• Update transactions local validation: addition of a minimal amount on outputs
• Update of the expected version for each document
• Adding local and global validations in the outline