de0_nano: add spi0 to de0_nano
cores/jp_vpi, cores/mor1kx-dev-env/mor1kx-dev-env.core: add missing CAPI key
de0_nano: connect AD-converter on SPI1
de0_nano: reassign UART pins to make room for SPI, tidier header allocation and I2C
de0_nano: add SPI2 to be able to connect external peripherals
de0_nano: reorder intercon according to IO addresses
de0_nano: fixup compile errors to make SPI finally work