ADR docs: justify a new CMS app for course to library import

[cmltaWt0]

Implementing the Epic-11.5 of Library Overhaul project we a going to create a new CMS app course_to_library_import.
This ADR is intented to be a justification of the app creation along with some architecture details of the app.

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[bradenmacdonald]

Could you mention how this compares to #27715 and/or if we'll be removing that code as part of this work?

[cmltaWt0]

Could you mention how this compares to #27715 and/or if we'll be removing that code as part of this work?

Let me re-phase the Context part regarding the relation to the current import capabilities (I've incorrectly describe it).
The newly proposed solution (python and rest api) is intended to manage the ImportHistory objects/entities.
So basically the API will allow as to create an intention to start the Import process, review/edit it (remove some xblocks), choose the level of decomposition (aka what level of hierarchy to choose).

So I meant that we do not have this type of imports yet - will update the ADR.

I do not think we will replace the mentioned import API.