alif: Add initial port to Alif Ensemble MCUs.

This commit adds the beginning of a new alif port with support for Alif
Ensemble MCUs.  See https://alifsemi.com/

Supported features of this port added by this commit:
- UART REPL.
- TinyUSB support, for REPL and MSC.
- Octal SPI flash support, for filesystem.
- machine.Pin support.

General notes about the port:
- It uses make, similar to other bare-metal ports here.
- The toolchain is the standard arm-none-eabi- toolchain.
- Flashing a board can be done using either the built-in serial bootloader,
  or JLink (both supported here).
- There are two required submodules (one for drivers/SDK, one for security
  tools), both of which are open source and on GitHub.
- No special hardware or software is needed for development, just a board
  connected over USB.

OpenMV have generously sponsored the development of this port.

Signed-off-by: Damien George <damien@micropython.org>
Signed-off-by: iabdalkader <i.abdalkader@gmail.com>

ports/alif/qstrdefsport.h

@@ -0,0 +1,2 @@
+// qstrs specific to this port
+// *FORMAT-OFF*