revamp config JSON parsing (#12)

Makes config-consuming implementations cleaner, and avoids reliance on JSON1 through the SQLite used by SQLiteCpp (which in exotic scenarios like our JDBC bindings, can differ from the SQLite loading the extension).

Author: mlin

CMakeLists.txt

@@ -18,7 +18,7 @@ endif()
 FetchContent_Declare(
     sqlite_zstd_vfs
     GIT_REPOSITORY  https://github.com/mlin/sqlite_zstd_vfs.git
-    GIT_TAG         dadf93e
+    GIT_TAG         a90ed8b
 )
 FetchContent_MakeAvailable(sqlite_zstd_vfs)
 include_directories(${sqlite_zstd_vfs_SOURCE_DIR}/src)