Improve "Enable access for new devices"

[Yann R]

When "Enable access for new devices" is enabled in Serviio running on a laptop, you can get many new unwanted clients from different networks where you connect your computer.

It would be very useful to add a field next to this option so as to define a IP address filter and then allow new devices... only from a certain domain. For instance an extra field allowing the user to set: 192.168.0.* as devices allowed for new access.

Best regards.

[Yann R]

A sub-part of this could by achieved by the “Clear Device list” possibility https://bitbucket.org/xnejp03/serviio/issues/1183/clear-device-list