[Scons] Implement module dependency sorting.

Modules can now call:

env.module_add_dependencies(name: str, deps: list, optional: bool)

To add required or optional dependencies during the "can_build" step.

Required dependencies will be checked and the module will be not be
enabled when they are missing, printing a warning to notify the user.

modules/text_server_adv/SCsub

@@ -36,8 +36,8 @@ def make_icu_data(target, source, env):
 # Thirdparty source files
 
 thirdparty_obj = []
-freetype_enabled = env.module_check_dependencies("text_server_adv", ["freetype"], True)
-msdfgen_enabled = env.module_check_dependencies("text_server_adv", ["msdfgen"], True)
+freetype_enabled = "freetype" in env.module_list
+msdfgen_enabled = "msdfgen" in env.module_list
 
 if env["builtin_harfbuzz"]:
     env_harfbuzz = env_modules.Clone()