Gateway API Translator Should Support * Listener Hostnames

[danehans]

Currently, the translator requires a listener hostname to be specified. However, the Gateway spec states "*" should be used to match all hostnames when unspecified. Update the translator to support this requirement.

xref: #286 (comment)

[danehans]

@zirain please assign yourself if you can fix this bug.

[danehans]

cc: @arkodg @skriss

[zirain]

@danehans I can assign myself without permission, but will take a look at this.