add hrantzsch/keychain and link

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "subprojects/ixwebsocket"]
 	path = subprojects/ixwebsocket
 	url = https://github.com/machinezone/ixwebsocket
+[submodule "subprojects/keychain"]
+	path = subprojects/keychain
+	url = https://github.com/hrantzsch/keychain

CMakeLists.txt

@@ -8,6 +8,7 @@ set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/")
 
 option(USE_LIBHANDY "Enable features that require libhandy (default)" ON)
+option(USE_KEYCHAIN "Store the token in the keychain (default)" ON)
 
 find_package(nlohmann_json REQUIRED)
 find_package(CURL)
@@ -100,3 +101,13 @@ if (USE_LIBHANDY)
         target_compile_definitions(abaddon PRIVATE WITH_LIBHANDY)
     endif ()
 endif ()
+
+if (USE_KEYCHAIN)
+    find_package(keychain QUIET)
+    if (NOT keychain_FOUND)
+        message("keychain was not found and will be included as a submodule")
+        add_subdirectory(subprojects/keychain)
+        target_link_libraries(abaddon keychain)
+        target_compile_definitions(abaddon PRIVATE WITH_KEYCHAIN)
+    endif ()
+endif ()