Option to set static IP address for configured access point

[HipsterBrown]

With the current custom access point setup for the T2, when we call commands.setLanNetwork in lib/tessel/access-point.js the IP address of the access point is always set to 192.168.1.101. This may cause some issues, depending on a user's local network setup.

A potential solution is to add an option to the t2 ap command for passing a custom IP address to that network setup, i.e. t2 ap -n TestNetwork --ip 192.168.1.123. That IP address would need to be validated by having the correct number of characters in the correct format and then passed into an updated commands.setLanNetwork function within lib/tessel/access-point.js if that option is set.

[HipsterBrown]

This is being accomplished in the adhoc PR -> #845

[misfitonie]

Hi, if this ticket is still open, i'll be happy to work on it :)