Add AreaCode to Australia for overseas territories "OT"

[MrQQish]

Issue Description

As an enhancement to the OED Australia will benefit from another AreaCode to capture overseas territories and other miscellaneous offshore jurisdictions.

This has been used internally in our systems and on earlier versions of OasisLMF using the AreaCode "OT" until recently when the ODS validation of inputs became more strict and has been disallowed.

[benhayes21]

add in "blank" for backward compatibility in the converter

[MattDonovan82]

Yes we can add this code in for Aus overseas territories @MrQQish

[MattDonovan82]

closed as implemented in v3.2.0