[master] Several small patches

[master] Several small patches

Tidy up several small tickets
Correct parsing of DUID from config file, previously the LL type
was put in the wrong place in the DUID string.
[ISC-Bugs #20962]
Add code to parse "do-forward-updates" as well as "do-forward-update"
[ISC-Bugs #31328]
Remove log_priority as it isn't currently used.
[ISC-Bugs #33397]
Increase the size of the buffer used for reading interface information.
[ISC-Bugs #34858]