type issues for dgd, min q factor baudrate and some reference

[EstherLerouzic]

• max-diff-group-delay" should be decimal, 2digit is enough in my opinion
• "min-Q-factor" should be decimal, also 2 digit is enough I think
• int32 for baudrate does not permit 32e9 bauds or higher, decimal with 1 digit would be OK for this one