Create reference/debug Interpreter

[WireWhiz]

The philosophy of BraneScript is and always will be an AOT optimized JIT compiled first language.

However there are many benefits to having an interpreter backend as long as we primarily use jit backends for production use cases.

1. Reference base case
   When we're testing different backends and runtimes, tests can be run against the results of the interpreter. As it'll be a lot easier to visually verify that the interpreter is performing the correct operations, rather then decompiling asm.

2. Reference for the intended behavior of the runtime. When new backends are being created, if docs fail the interpreter code can be referenced

3. The interpreter could potentially be used for step-through debugging, possibly even while using a jit backend by manipulating the function table.

[WireWhiz]

I forgot the most important benefit: an interpreter runs on any architecture