find a solution to register limitations

So for a while now i have been pondering what to do with the issue of only having ram whilst having features in SMOL that require quite a bit of memory.

There are few things that could be done and am not too sure which one is best

- abuse `FX65` opcode for treating ROM like RAM
- revise the language to not have certain features like functions
- just error out like we always do even when function allocation for parameters

I feel like abusing opcodes is a bit nasty, so the most likely option for now is option 3. Option 3 is also the fastest one to build.