[BD-24] [TNL-7318] BB-2355: Move LTI configuration to models.

This change moves the LTI configuration retrieval to
a Django model that will LTI configuration.
The current model proxies back the to blocks to keep
backwards compatibility.

See reasoning for change at:
https://github.com/edx/xblock-lti-consumer/blob/master/docs/decisions/0001-lti-extensions-plugin.rst

Send modal to parent window.

Because the courseware microfrontend loads units inside iframes,
the LTI modal ends up being squished and generally ugly.
This PR introduces a new message sent to the parent window to request
a modal containing the contents of the LTI launch iframe.

https://openedx.atlassian.net/browse/TNL-7410

[BD-24] [TNL-7318]: BB-2355 - Add decoding and scope verification methods

Convert is_past_due to a method

This is just to keep it in line with other xblocks that define
an is_past_due attribute. Nicer if they all have the same access
pattern.

[BD-29] [TNL-6993] [BB-2706] Make LTI Consumer indexable

BOM-1953 : Replace pycryptodome with pycryptodomex

[BD-18] remove nose footprints from the project

Merge pull request #87 from open-craft/patrick/BB-2516-lti-improvements-implement-context-claim-on-lti

[BD-24] [TNL-7316] Implement context claim on LTI 1.3

[BD-2] [BB-2612]: Add ADR to define LTI Plugin architecture implementation

Removed usages of package six

Find all packages in setup.py

Merge pull request #77 from open-craft/patrick/BB-2523-add-support-for-lti-embeds-in-the-course-tabs-a

BD-02 BD-03 Add support for LTI embeds in course tabs and elsewhere

Include new packages in distribution

Renamed module to avoid import confusion

Removed deprecated future imports

[BD-2] BB-2365: Merge LTI 1.3 support to master. 

k# Please enter the commit message for your changes. Lines starting

Also fixes a few untreated exceptions and remove unused variables.

Signed-off-by: Giovanni Cimolin da Silva <giovannicimolin@gmail.com>