Adds rudimentary support for the Arrow DECA board (see also the user manual) including the clocks, LEDs, switches, buttons and GPIO connectors as well as setitng the correct voltages for the I/O banks. The board features the Intel Altera MAX10 (10M50DAF484C6GES) FPGA.

There are more peripherals like the ADV7513 for HDMI TX, the TI TLV320AIC3254 24-bit audio codec, an SD card reader, etc. but this commit does not add support for those due to the varying voltages required for the different pins in a lot of cases. In addition, I would like to test any further additions thoroughly before committing them :).

To set the I/O bank voltages correctly, and to make sure Quartus doesn't complain (see also Tom Verbeure's blog post), we have to specify some additional set_global_assignment directives to the QSF file by overriding the file_templates() method.

I tested the board successfully with Blinky.