Introduce Rust FSBL

This PR introduces some major features while also changing the project structure to be more flexible
for multiple platforms (e.g. host tooling). It also includes a lot of
bugfixes, renamings for consistency purposes and dependency updates.

Added features:

1. Pure Rust FSBL for the Zedboard. This first variant is simplistic. It
   is currently only capable of QSPI boot. It searches for a bitstream
   and ELF file inside the boot binary, flashes them and jumps to them.
2. QSPI flasher for the Zedboard.
3. DDR, QSPI, DEVC, private CPU timer and PLL configuration modules
3. Tooling to auto-generate board specific DDR and DDRIOB config
   parameters from the vendor provided ps7init.tcl file

Changed project structure:

1. All target specific project are inside a dedicated workspace inside
   the `zynq` folder now.
2. All tool intended to be run on a host are inside a `tools` workspace
3. All other common projects are at the project root

Major bugfixes:

1. SPI module: CPOL was not configured properly
2. Logger flush implementation was empty, implemented properly now.

zedboard-fpga-design/src/zedboard-bd.tcl

@@ -675,6 +675,18 @@ proc create_root_design { parentCell } {
   connect_bd_net -net xlslice_0_Dout1 [get_bd_pins UART_MUX/Dout] [get_bd_pins uart_mux_0/sel]
   connect_bd_net -net xlslice_1_Dout [get_bd_pins EMIO_O_0/Dout] [get_bd_pins LEDS/Din] [get_bd_pins EMIO_I/In0] [get_bd_pins UART_MUX/Din]
 
+  # Set DDR properties specified in the datasheet.
+  set_property -dict [list \
+    CONFIG.PCW_UIPARAM_DDR_BOARD_DELAY0 {0.410} \
+    CONFIG.PCW_UIPARAM_DDR_BOARD_DELAY1 {0.411} \
+    CONFIG.PCW_UIPARAM_DDR_BOARD_DELAY2 {0.341} \
+    CONFIG.PCW_UIPARAM_DDR_BOARD_DELAY3 {0.358} \
+    CONFIG.PCW_UIPARAM_DDR_DQS_TO_CLK_DELAY_0 {0.025} \
+    CONFIG.PCW_UIPARAM_DDR_DQS_TO_CLK_DELAY_1 {0.028} \
+    CONFIG.PCW_UIPARAM_DDR_DQS_TO_CLK_DELAY_2 {-0.009} \
+    CONFIG.PCW_UIPARAM_DDR_DQS_TO_CLK_DELAY_3 {-0.061} \
+  ] [get_bd_cells processing_system7_0]
+
   # Create address segments
   assign_bd_address -offset 0x43C00000 -range 0x00010000 -target_address_space [get_bd_addr_spaces processing_system7_0/Data] [get_bd_addr_segs axi_uart16550_0/S_AXI/Reg] -force
   assign_bd_address -offset 0x42C00000 -range 0x00010000 -target_address_space [get_bd_addr_spaces processing_system7_0/Data] [get_bd_addr_segs axi_uartlite_0/S_AXI/Reg] -force