[VM/eval] Fix pending issues, add unit-tests & cleanup

[drkameleon]

Description

This PR ended up being far more important than initially planned but it was for a very good reason: there were deep-hidden issues that could not have been solved but via a very radical approach.

So, what does this PR do?

• Introduce a new intermediate representation (AST), between the parser and the evaluator
• Given this new representation we can:
  • Perform optimizations on the node level (e.g. constant folding, complicated arithmetic simplifications, etc)
  • Optimize the constructs we already were, but in a much safer - and hopefully performant - way
  • All syntactic sugar is/should-be working flawlessly: ->, =>, | (and any combinations thereof) ❗
• Complete rewrite of the Evaluator (VM/eval), from scratch
• Added more bytecode optimizations in the evaluator (e.g. opStorl), which was only limited to the now-obsolete optimizer and not even in use before
• The code is far (far...) cleaner and easier to debug and reason about
• Re-organized our opCode set
• Make Built-in functions that correspond to a specific opCode "carry" this opCode as an internal field

Basically, pure bliss! lol 🎉 (seriously now: you cannot imagine how satisfied I am after all of this work!)

Apart from the fixes mentioned below and some general cleanup, this PR - inspired by the awesome work by @RickBarretto - will also attempt to add thorough tests that verify the very important job of the VM's evaluator + AST, as well as revisit previously-written Rosetta Code examples, rewrite any that need rewriting & add the ones that are valid - and perform well enough with the latest version - to our CI builds (= to be executed as part of the Tester tool). 🚀

---

• Fixes Inconsistent behavior for => syntactic sugar #799
• Fixes [Eval\addTerminalValue] Verify pipe operators are working #802
• Fixes [VM/eval] to be fixed #803
• Fixes [VM/eval] Inline blocks not evaluated correctly #804
• Fixes [eval/optimizeSwitch] switch not always processed correctly #817

---

Type of change

• Code cleanup
• Bug fix (non-breaking change which fixes an issue)

[drkameleon]

First successful CI build after 1,234,567 tries! 🎉

[drkameleon]

As unbelievable as this sounds, this mega-PR is to be considered complete. 🎉

So, until a monster emerges and devours it all, let's say it's...

...ready to merge! 🚀

[dumblob]

Congratulations!

I did not have the time to look at this and I am pretty sure I will not read everything (it is really long!). But I will at least take a look at certain parts which interest me - maybe arithmetic - decimal vs. floating point, maybe a few bytecode optimizations (will compare to FastVM/minivm and to the approaches in recent Python release bytecode changes and maybe even compared to JIT in clover), maybe even some "reactiveness", etc.