Allow Rust testprograms

[TeyKey1]

Currently only test programs written in assembly are supported as Hive testprograms. The reason for that is that it can be easily ensured that the ARM and RISCV testprograms only use the very base functionality of the instruction sets to ensure that the testprograms run on any target available on the testrack.

It should also be possible to achieve such functionality using Rust programs. There's some advantages to this:

• Toolchain installation on the testserver becomes much easier as building etc can be done through cargo
• No need to write assembly
• Overall testprogram logic in the monitor binary should become much simpler

Some things that need to be figured out are the following:

• Hive defines still need to be able to be dynamically linked to the testprogram for every build/test run
• It needs to be ensured that the submitted testprograms build and conform to the restrictions of the most basic ARM/RISCV instruction sets