[mod] documentation: change the jinja context doesn't depend on searx.webapp

Before this commit, in the documentation, the jinja context is 'webapp' and contains
the global variable in the searx.webapp module.

This commit changes this to include only the mandatory variables to build the
documentation.

docs/admin/engines.rst

@@ -46,7 +46,7 @@ Show errors   **DE**
 
 .. _configured engines:
 
-.. jinja:: webapp
+.. jinja:: searx
 
    .. flat-table:: Engines configured at built time (defaults)
       :header-rows: 1

docs/admin/plugins.rst

@@ -14,7 +14,7 @@ Configuration defaults (at built time):
 
 .. _configured plugins:
 
-.. jinja:: webapp
+.. jinja:: searx
 
    .. flat-table:: Plugins configured at built time (defaults)
       :header-rows: 1

docs/conf.py

@@ -27,9 +27,15 @@ numfig = True
 
 exclude_patterns = ['build-templates/*.rst']
 
-from searx import webapp
+import searx.search
+import searx.engines
+import searx.plugins
+searx.search.initialize()
 jinja_contexts = {
-    'webapp': dict(**webapp.__dict__),
+    'searx': {
+        'engines': searx.engines.engines,
+        'plugins': searx.plugins.plugins
+    },
 }
 
 # usage::   lorem :patch:`f373169` ipsum

docs/dev/reST.rst

@@ -1289,15 +1289,21 @@ build chapter: :ref:`engines generic`.  Below the jinja directive from the
    :language: reST
    :start-after: .. _configured engines:
 
-The context for the template is selected in the line ``.. jinja:: webapp``.  In
-sphinx's build configuration (:origin:`docs/conf.py`) the ``webapp`` context
-points to the name space of the python module: ``webapp``.
+The context for the template is selected in the line ``.. jinja:: searx``.  In
+sphinx's build configuration (:origin:`docs/conf.py`) the ``searx`` context
+contains the ``engines`` and ``plugins``.
 
 .. code:: py
 
-   from searx import webapp
+   import searx.search
+   import searx.engines
+   import searx.plugins
+   searx.search.initialize()
    jinja_contexts = {
-       'webapp': dict(**webapp.__dict__)
+      'searx': {
+         'engines': searx.engines.engines,
+         'plugins': searx.plugins.plugins
+      },
    }