add generate username engine

[zpcol]

if you can insert a file, https://github.com/Kunzisoft/KeePassDX/issues/700

a good idea if you can also generate username by attaching list as text file. and automatically formats that username to lowercase without spaces without periods without any other letter marks.

in insertion section, separated between a list of male and female names.

sorry if it's a hassle, I use OpenHub app and there is no label feature. thanks.

[Gottarocket]

I am not sure if this is similar but would be helpful if there is random username generator like random password generator

[Bugaddr]

Thats actually a good idea, like markov chains can be used for generation of random usernames