Move guassopt to optics/guassopt

This is a PR to move ```sympy.physics.guassopt``` to ```sympy.physics.optics.guassopt```.
This is the wrong approach. Use the following patch instead (let me know if it works):
```diff
diff --git a/sympy/utilities/runtests.py b/sympy/utilities/runtests.py
index 0875405..3538c3b 100644
--- a/sympy/utilities/runtests.py
+++ b/sympy/utilities/runtests.py
@@ -554,7 +554,8 @@ def _doctest(*paths, **kwargs):
         "doc/src/modules/mpmath",  # needs to be fixed upstream
         "sympy/mpmath",  # needs to be fixed upstream
         "doc/src/modules/plotting.rst",  # generates live plots
-        "sympy/utilities/compilef.py"  # needs tcc
+        "sympy/utilities/compilef.py",  # needs tcc
+        "sympy/physics/gaussopt.py", # raises deprecation warning
     ])
 
     if import_module('numpy') is None:
```