Deprecation/Removal: lti_module DEPR-11

[Michael Terry]

Hi there,

We plan to remove the deprecated xmodule lti_module. We are targeting
removal after the 23rd of January. (xblock-lti-consumer is the
non-deprecated replacement.)

Please read https://openedx.atlassian.net/browse/DEPR-11 for more
information and to post any questions/comments. The proposed deadline
for comments before acceptance is the 16th of January.

Thanks.