Screen casting for UT devices using the MIR display server.

This app was inspiered by the book "What I have learned about the Ubuntu mobile phone BQ Aquaris E4.5" in gitbook at : https://www.gitbook.com/book/gurucubano/bq-aquaris-e-4-5-ubuntu-phone

Also inspiered by the UBports documentation at https://docs.ubports.com/en/latest/userguide/advanceduse/screencasting.html :)