refactor: use include syntax for wasi:clocks

This commit uses `include` syntax to simplify the proxy world
by hiding the interfaces from wasi:clock package

Signed-off-by: Jiaxiao Zhou (Mossaka) <duibao55328@gmail.com>

Author: Mossaka

wit/proxy.wit

@@ -5,9 +5,8 @@ package wasi:http@0.2.0-rc-2023-11-10;
 /// this world may concurrently stream in and out any number of incoming and
 /// outgoing HTTP requests.
 world proxy {
-  /// HTTP proxies have access to time and randomness.
-  import wasi:clocks/wall-clock@0.2.0-rc-2023-11-10;
-  import wasi:clocks/monotonic-clock@0.2.0-rc-2023-11-10;
+  // HTTP proxies have access to time and randomness.
+  include wasi:clocks/imports@0.2.0-rc-2023-11-10;
   import wasi:random/random@0.2.0-rc-2023-11-10;
 
   /// Proxies have standard output and error streams which are expected to