Add "personium-localunit:" support when registering external Role

[dixonsiu]

Issue

Sometimes the Cell and target external Role are not from the same Personium Unit.
For detail specifications, please refer to the API Reference.

REST API URL:

    "https://{UnitFQDN1}/{CellName1}/__ctl/ExtRole"

External Role URL:

    "ExtRole": "https://{UnitFQDN2}/{CellName2}/__role/__/{ExtRoleName}"

Solution

Should compare the UnitFQDN whether "personium-localunit" is applicable.

To Dos

Should convert same Unit FQDN to personium-localunit

1. External Role Registration
2. External Cell Registration
3. Display List