[IDE] recent used boards list

[pavel-b-kr12]

Is will be very useful to have a list, filled with recent used boards. So we will not spend time searching in menus.
Also this will partially solve questions e.g.:
1
2
3
about remove-unused-boards and keep it up-to-date

[per1234]

This has already been implemented in #8607

It's available now in the beta build of the Arduino IDE if you want to try it out:
https://www.arduino.cc/en/Main/Software#beta