added cms_query_rewrite.tmpl which was forgotten

it had to go along with commit 74c6963b386496c6e9bc9197ec9f383e7a760599 in https://github.com/dmwm/DAS/pull/4051
added a note on output sanitization
Merge pull request #4068 from dmwm/qrewrite_tmpl_fix

added cms_query_rewrite.tmpl which was not added into git in earlier commit/pull
some pylint and pep8 fixes

* now all files in keywordsearch package get >=9 in pylint
* still to remove TODOs, and (some disabled msgs?)
* still some code may be cleaned up further