deps: move json/httplib to CPM

cmake/CPM.cmake

@@ -35,8 +35,12 @@ endif()
 include(${CPM_DOWNLOAD_LOCATION})
 
 # Set CPM options for better caching and performance
-set(CPM_USE_LOCAL_PACKAGES ON)
-set(CPM_LOCAL_PACKAGES_ONLY OFF)
+if(NOT DEFINED CPM_USE_LOCAL_PACKAGES)
+  set(CPM_USE_LOCAL_PACKAGES OFF)
+endif()
+if(NOT DEFINED CPM_LOCAL_PACKAGES_ONLY)
+  set(CPM_LOCAL_PACKAGES_ONLY OFF)
+endif()
 set(CPM_DONT_CREATE_PACKAGE_LOCK ON)
 set(CPM_DONT_UPDATE_MODULE_PATH ON)
 set(CPM_DONT_PREPEND_TO_MODULE_PATH ON)
@@ -46,4 +50,3 @@ if(DEFINED ENV{GITHUB_ACTIONS})
   set(CPM_SOURCE_CACHE "$ENV{HOME}/.cpm-cache")
   message(STATUS "CPM cache directory: ${CPM_SOURCE_CACHE}")
 endif()
-