chore: bump full-node to 2.0.0; stop tracking the generated manifest

Set project(ObsidianDragon VERSION 2.0.0) (was 1.3.0); the lite variant keeps
its own independent DRAGONX_LITE_VERSION (1.0.0). res/ObsidianDragon.manifest is
generated per-variant by configure_file from res/ObsidianDragon.manifest.in, so
it was wrongly tracked (it kept showing dirty, stamped with whichever variant
built last) - untrack it and gitignore it; the .in template remains the source.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CMakeLists.txt

@@ -15,7 +15,7 @@ if(APPLE)
 endif()
 
 project(ObsidianDragon
-    VERSION 1.3.0
+    VERSION 2.0.0
     LANGUAGES C CXX
     DESCRIPTION "DragonX Cryptocurrency Wallet"
 )