Error when group with leading zeroes validated

Closes #12

See merge request !16

group id if it had leading zeroes. Removed the conversion of the id
to an int when passing to get_or_create_group_by_groupid(). Unnecessary
as the id was already validated with a regex.

The tests require a connection to the live lookup server

Closes #13

See merge request !15

invoke_method to return lookup results expected by the tests.

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