feat(security): Add user confirmation/reauth for sensitive changes Auditors can raise Reauth(reason) exception to require the user to enter a token (e.g. account password) to verify the user is performing the change. Naming is subject to change. actions.py: New ReauthAction class handler and verifyPassword() method for overriding if needed. client.py: Handle Reauth exception by calling Client:reauth() method. Default client:reauth method. Add 'reauth' action declaration. exceptions.py: Define and document Reauth exception as a subclass of RoundupCGIException. templating.py: Define method utils.embed_form_fields(). The original form making a change to the database has a lot of form fields. These need to be resubmitted to Roundup as part of the form submission that verifies the user's password. This method turns all non file form fields into type=hidden inputs. It escapes the names and values to prevent XSS. For file form fields, it base64 encodes the contents and puts them in hidden pre blocks. The pre blocks have data attributes for the filename, filetype and the original field name. (Note the original field name is not used.) This stops the file content data (maybe binary e.g. jpegs) from breaking the html page. The reauth template runs JavaScript that turns the encoded data inside the pre tags back into a file. Then it adds a multiple file input control to the page and attaches all the files to it. This file input is submitted with the rest of the fields. _generic.reauth.html (multiple tracker templates): Generates a form with id=reauth_form to: display any message from the Reauth exception to the user (e.g. why user is asked to auth). get the user's password submit the form embed all the form data that triggered the reauth recreate any file data that was submitted as part of the form and generate a new file input to push the data to the back end It has the JavaScript routine (as an IIFE) that regenerates a file input without user intervention. All the TAL based tracker templates use the same form. There is also one for the jinja2 template. The JavaScript for both is the same. reference.txt: document embed_form_fields utility method. upgrading.txt: initial upgrading docs. TODO: Finalize naming. I am leaning toward ConfirmID rather than Reauth. Still looking for a standard name for this workflow. Externalize the javascript in _generic.reauth.html to a seperate file and use utils.readfile() to embed it or change the script to load it from a @@file url. Clean up upgrading.txt with just steps to implement and less feature detail/internals. Document internals/troubleshooting in reference.txt. Add tests using live server.

=========================
Roundup Tracker Templates
=========================

The templates distributed with Roundup are stored in the "share" directory
nominated by Python. On Unix this is typically
``/usr/share/roundup/templates/`` (or ``/usr/local/share...``) and
on Windows this is ``c:\python38\share\roundup\templates\``.

The template loading looks in four places to find the templates:

1. *share* - eg. ``<prefix>/share/roundup/templates/*``.
   This should be the standard place to find them when Roundup is
   installed running setup.py from source.
2. ``install_dir``/../<prefix>/share/....``, where prefix is the
   Python's ``sys.prefix``. ``sys.base_prefix`` or 
   `sys.base_prefix/local``. This finds templates (and locales)
   installed by pip. E.G. in a virtualenv located at (``sys.prefix``):
   ``/tools/roundup``, roundup would be at:
   ``/tools/roundup/lib/python3.7/site-packages/roundup``. The
   templates would be at:
   ``/tools/roundup/lib/python3.7/site-packages/tools/roundup/share/roundup/templates/``. (Replace 3.7 with the Python version you are running.)
3. ``<roundup.admin.__file__>/../../share/roundup/templates/*``.
   This will be used if Roundup's run in the distro (aka. source)
   directory.
4. ``<current working dir>/*``.
   This is for when someone unpacks a 3rd-party template.
5. ``<current working dir>``.
   This is for someone who "cd"s to the 3rd-party template dir.

Templates contain:

- modules ``schema.py`` and ``initial_data.py``
- directories ``html``, ``detectors`` and ``extensions``
  (with appropriate contents)
- optional directory ``lib`` which contains modules used by the other
  tracker components
- optional ``config_ini.ini`` file. It is structured like a tracker's
  ``config.ini`` but contains only headers (e.g. ``[main]``) and
  *required* parameters that are different from defaults. For example::
  
    [main]
    template_engine = jinja2

    static_files = static

  These settings override the default values in the tracker's
  ``config.ini`` when using roundup-admin to install a template.
- template "marker" file ``TEMPLATE-INFO.txt``, which contains
  the name of the template, a description of the template
  and its intended audience.

  An example TEMPLATE-INFO.txt:

  .. code-block:: text

     Name: classic
     Description: This is a generic issue tracker that may be used to
		  track bugs, feature requests, project issues or any
		  number of other types of issues. Most users of
		  Roundup will find that this template suits them,
		  with perhaps a few customisations.
     Intended-For: All first-time Roundup users