Access point fixes

[rjwats]

add lingering mode to access point
fix bug which prevents active access point from being re-configured

[kasedy]

nit: I prefer ApProvisionMode over APProvisionMode

Is it possible to add a tooltip over the status icon to indicate that AP point may stay active while users are connected. Reset the device to drop users and disable AP point.

[rjwats]

Yes. I prefer the "ApProvisionMode" naming style too - it avoids the possiblity of silly names like APHTTPEndpoint.

The underlying libaries obviously don't all adher to a single naming convention: such as FS, ArduinoOTAClass and the 'softAPgetStationNum()' and 'softAPIP()' functions. My brain hates the inconsistancy within a class more than it cares about my preferred naming style so I choose to carry the underlying naming through :) (but yeah - boo for upper case acronyms.)