Mark known devices and look for new ones automatically

**Is your feature request related to a problem? Please describe.**
Hi, I really like your tool, it has a lot of functionality and it's very light, but I think it could become even more complete with some features that I think are easy to implement.

**Describe the solution you'd like**

1) ability to recognize devices one by one, so that you can detect new unrecognized devices


2) Automatic scanning at regular intervals


3) Alert (display of a message window) when a new device is detected in the network, not yet validated by the user in the "Angry IP Scanner" tool, this could allow to secure his network in case of suspicious connection.


4) option to execute a command when detecting a new device not yet enabled by the user


**After the integration of these features, your tool will be the most complete in its category**