Missing feature: a user/group cannot be selected twice.

Closes #15

See merge request !14

Missing feature: a "self" selection should be locked

Closes #14

See merge request !13

So we implement it ourselves by filtering out pre-selected items in the
processResults callback.

solution suggested on stack overflow - namely, as each selection tag is
rendered add a custom class if it's the principle user.

Relevant posts:
  https://stackoverflow.com/questions/16564425/how-to-implement-select2-with-lock-selection/48111387#48111387
  https://jsfiddle.net/o3s3y42e/4/

Upgrade to use select2 version 4.

Closes #11

See merge request !12

Also refactored validate_crsids() into validate_crsids() and
validate_crsid_list().

style of both the container and dropdown elements of both the user and
group controls. See https://select2.org/configuration/options-api
and *CssClass.

crsids. Also added method convert_query_dict(query_dict): works around
the problems django has with validating a request parameter array.

This is a breaking change and the upgrade path will be detailed in the
README. However the main change is that the consumer will need to use
<select> instead of <input>.

Update Select2 (to latest v3) and jQuery libraries

Closes #11

See merge request !11

Update ibisclient to version 1.2.10

Closes #10

See merge request !10

Update setup.py to show up to date information

See merge request !8

To render properly on PyPI the long description needs to have its
content type set.

The setuptools version of setup() has some features which make it work
better with the modern pip ecosystem.

add Auto-DevOps GitLab CI template

Closes #7

See merge request !7

Bring in the Auto-DevOps template from GitLab. We do our own matrix
testing but this brings in the various security, lecence and dependency
scanning tools from Auto-DevOps.

In order to make use of these scanning tools we build a small container
but this is not intended to run the application, just to contain the
source so that the various scanners can scan it. That being said we do
"pip install" within the container so that a basic "pip install" test
must pass before we start all the rest of the test jobs.

Closes #7

Support authenticated connections

Closes #5

See merge request !6

Add support for optional settings that will allow users to authenticate and use django-ucamlookup outside the CUDN.

add GitLab CI configuration for testing

Closes #6

See merge request !5

Add a basic CI configuration which matrix tests against supported
Python and Django versions along with running flake8 and code-coverage.
Coverage information is extracted from the coverage job run.

Closes #6

Add tox support for matrix testing