[mod] typification of SearXNG: add new result type Paper

This patch adds a new result type: Paper

- Python class:   searx/result_types/paper.py
- Jinja template: searx/templates/simple/result_templates/paper.html
- CSS (less)      client/simple/src/less/result_types/paper.less

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

docs/dev/result_types/main/paper.rst

@@ -0,0 +1,7 @@
+.. _result_types.paper:
+
+=============
+Paper Results
+=============
+
+.. automodule:: searx.result_types.paper

docs/dev/result_types/main_result.rst

@@ -16,6 +16,7 @@ following types have been implemented so far ..
    main/mainresult
    main/keyvalue
    main/code
+   main/paper
 
 The :ref:`LegacyResult <LegacyResult>` is used internally for the results that
 have not yet been typed.  The templates can be used as orientation until the
@@ -26,7 +27,6 @@ final typing is complete.
 - :ref:`template videos`
 - :ref:`template torrent`
 - :ref:`template map`
-- :ref:`template paper`
 - :ref:`template packages`
 - :ref:`template files`
 - :ref:`template products`