docs folder restructure

Author: keflavich

docs/xmm_newton/xmm_newton.rst renamed to docs/esa/xmm_newton.rst

@@ -195,7 +195,7 @@ The following modules have been completed using a common API:
   vsa/vsa.rst
   xmatch/xmatch.rst
   dace/dace.rst
-  xmm_newton/xmm_newton.rst
+  esa/xmm_newton.rst
 
 
 These others are functional, but do not follow a common & consistent API:
@@ -290,7 +290,7 @@ generally return a table listing the available data first.
   ukidss/ukidss.rst
   vsa/vsa.rst
   skyview/skyview.rst
-  xmm_newton/xmm_newton.rst
+  esa/xmm_newton.rst
 
 Simulations
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