d/config: re-organize decompiler/config and eliminate most of the duplication (#2185)

Reasons for doing so include:
1. This should stop the confusion around editing the wrong config file's
flags -- when for example, extracting a level. Common settings can be in
one central place, with bespoke overrides being provided for each
version
2. Less verbose way of supporting multiple game versions. You don't have
to duplicate the entire `type_casts` file for example, just add or
override the json objects required.
3. Makes the folder structure consistent, Jak 1's `all-types` is now in
a `jak1` folder, etc.

test/decompiler/test_DataParser.cpp

@@ -17,7 +17,7 @@ class DataDecompTest : public ::testing::Test {
 
   static void SetUpTestCase() {
     dts = std::make_unique<DecompilerTypeSystem>(GameVersion::Jak1);
-    dts->parse_type_defs({"decompiler", "config", "all-types.gc"});
+    dts->parse_type_defs({"decompiler", "config", "jak1", "all-types.gc"});
   }
 
   static void TearDownTestCase() { dts.reset(); }