Refactor session db logging and key generation for sessions/otks While I was working on the redis sessiondb stuff, I noticed that log_wanrning, get_logger ... was duplicated. Also there was code to generate a unique key for otks that was duplicated. Changes: creating new sessions_common.py and SessionsCommon class to provide methods: log_warning, log_info, log_debug, get_logger, getUniqueKey getUniqueKey method is closer to the method used to make session keys in client.py. sessions_common.py now report when random_.py chooses a weak random number generator. Removed same from rest.py. get_logger reconciles all logging under roundup.hyperdb.backends.<name of BasicDatabase class> some backends used to log to root logger. have BasicDatabase in other sessions_*.py modules inherit from SessionCommon. change logging to use log_* methods. In addition: remove unused imports reported by flake8 and other formatting changes modify actions.py, rest.py, templating.py to use getUniqueKey method. add tests for new methods test_redis_session.py swap out ModuleNotFoundError for ImportError to prevent crash in python2 when redis is not present. allow injection of username:password or just password into redis connection URL. set pytest_redis_pw envirnment variable to password or user:password when running test.

<tal:block metal:use-macro="templates/page/macros/icing">
<title metal:fill-slot="head_title" i18n:translate=""
 >List of files - <span tal:replace="config/TRACKER_NAME" i18n:name="tracker" /></title>
<span metal:fill-slot="body_title" tal:omit-tag="python:1"
  i18n:translate="">List of files</span>
<td class="content" metal:fill-slot="content">

<table class="otherinfo" tal:define="batch request/batch">
 <tr><th style="padding-right: 10" i18n:translate="">Download</th>
     <th style="padding-right: 10" i18n:translate="">Description</th>
     <th style="padding-right: 10" i18n:translate="">Content Type</th>
     <th style="padding-right: 10" i18n:translate="">Uploaded By</th>
     <th style="padding-right: 10" i18n:translate="">Date</th>
 </tr>
 <tr tal:repeat="file batch" tal:attributes="class python:['normal', 'alt'][repeat['file'].index%6//3]">
  <td>
   <a tal:attributes="href string:file${file/id}/${file/name}"
      tal:content="file/name">dld link</a>
  </td>
  <td tal:content="file/description">description</td>
  <td tal:content="file/type">content type</td>
  <td tal:content="file/creator">creator's name</td>
  <td tal:content="file/creation">creation date</td>
 </tr>

 <metal:block use-macro="templates/issue.index/macros/batch-footer" />

</table>

</td>

</tal:block>