Add LTI configuration variable trustExternalLTISystems

[christianhueserhzdr]

As of now the LTI configuration variables do not contain the case for trustExternalLTISystems:

{% if lti is defined %}
  lti:
    enabled: true
    id: artemis_lti
    oauth-key: artemis_lti_key
    oauth-secret: {{ lti.oauth_secret }}
    trustExternalLTISystems: {{ lti.trustExternalLTISystems | default(false) | to_json }}
{% endif %}

See template for application-prod.yml

This is also the case for the environment variables:

{% if lti is defined %}
ARTEMIS_LTI_ENABLED='true'
ARTEMIS_LTI_ID='artemis_lti'
ARTEMIS_LTI_OAUTHKEY='artemis_lti_key'
ARTEMIS_LTI_OAUTHSECRET='{{ lti.oauth_secret }}'
{% endif %}

See template for artemis.env

In order to make LTI work properly in our case we also need trustExternalLTISystems.

Proposal:

application-prod.yml.j2

{% if lti is defined %}
  lti:
    enabled: true
    id: artemis_lti
    oauth-key: artemis_lti_key
    oauth-secret: {{ lti.oauth_secret }}
    trustExternalLTISystems: {{ lti.trustExternalLTISystems | default(false) | to_json }}
{% endif %}

artemis.env.j2

{% if lti is defined %}
ARTEMIS_LTI_ENABLED='true'
ARTEMIS_LTI_ID='artemis_lti'
ARTEMIS_LTI_OAUTHKEY='artemis_lti_key'
ARTEMIS_LTI_OAUTHSECRET='{{ lti.oauth_secret }}'
ARTEMIS_LTI_TRUSTEXTERNALLTISYSTEMS='{{ lti.trustExternalLTISystems | default(false) | to_json }}'
{% endif %}

Would it be possible to extend the Ansible Collection by this variable? If yes, I'll create a PR for that.