big steps torwards an efficient, simple IC implementation (#16543)

* reworked ID handling
* the packed AST now has its own ID mechanism
* basic serialization code works
* extract rodfiles to its own module
* rodfiles: store and compare configs
* rodfiles: store dependencies
* store config at the end
* precise dependency tracking
* dependency tracking for rodfiles
* completed loading of PSym, PType, etc
* removed dead code
* bugfix: do not realloc seqs when taking addr into an element
* make IC opt-in for now
* makes tcompilerapi green again
* final cleanups

Co-authored-by: Andy Davidoff <github@andy.disruptek.com>

tests/compilerapi/tcompilerapi.nim

@@ -18,7 +18,7 @@ import std / [os]
 
 proc initInterpreter(script: string): Interpreter =
   let std = findNimStdLibCompileTime()
-  result = createInterpreter(script , [std, parentDir(currentSourcePath),
+  result = createInterpreter(script, [std, parentDir(currentSourcePath),
     std / "pure", std / "core"])
 
 proc main() =