IC: next steps (#16550)

* cleanups
* ast.nim: cleanups
* IC: no more sym.tab field, stored externally in the module graph
* nimble compiles again
* rodfiles: store bitwidth of integers and the endianness in the cookie because we serialize 'int' directly
* rodfiles: added compilerproc and export sections
* rodfiles: added all the missing sections
* rodfiles: track the missing information
* IC: architecture for lazy loading of proc bodies
* make tests green again
* completed the lazy loading of proc bodies
* symbol lookup integration, part 1
* symbol lookup integration, part 2
* symbol lookup integration, part 3
* make tcompilerapi work again
* rodfiles: fixed config change handling

compiler/ic/packed_ast.nim

@@ -16,28 +16,6 @@ import std / [hashes, tables, strtabs, md5]
 import bitabs
 import ".." / [ast, options]
 
-const
-  localNamePos* = 0
-  localExportMarkerPos* = 1
-  localPragmaPos* = 2
-  localTypePos* = 3
-  localValuePos* = 4
-
-  typeNamePos* = 0
-  typeExportMarkerPos* = 1
-  typeGenericParamsPos* = 2
-  typePragmaPos* = 3
-  typeBodyPos* = 4
-
-  routineNamePos* = 0
-  routineExportMarkerPos* = 1
-  routinePatternPos* = 2
-  routineGenericParamsPos* = 3
-  routineParamsPos* = 4
-  routineResultPos* = 5
-  routinePragmasPos* = 6
-  routineBodyPos* = 7
-
 const
   nkModuleRef* = nkNone # pair of (ModuleId, SymId)
 
@@ -55,7 +33,6 @@ type
   TypeId* = PackedItemId
 
 const
-  nilTypeId* = PackedItemId(module: LitId(0), item: -1.int32)
   nilItemId* = PackedItemId(module: LitId(0), item: -1.int32)
 
 const