Remove the implementer agreements and merge them into the official documentation/spec

Description of the proposal:

I do not see the reason to have a separate set of implementer agreements - which are essentially meeting notes - as a separate location to see how things must be implemented. I think they can be systematically merged into the documentation text, and if we're lucky in some cases into the spec itself (in EXPRESS, or UML in the future)

Describe how it contributes to the objectives set in https://github.com/buildingSMART/NextGen-IFC/wiki/Towards-a-technology-independent-IFC:

What do we win:

Less confusion. Single source of truth. Less maintenance.

What do we loose

Nothing?

Schema impact:

Case by case based on implementer agreement.

Instance model impact:

Case by case based on implementer agreement.

Backwards compatible:

Case by case based on implementer agreement.

Automatic migration possible:

No.

Additional implications:

-
Note that not all points need to be satisfied!
Backwards compatibility and file size are not concerns.

The issue names no files or tests; begin by locating the implementer agreements and the official documentation/spec, including the EXPRESS or future UML material mentioned. Define the agreement-by-agreement merge scope and verify that the separate agreements no longer remain a conflicting source of truth.

Written by the indexing model from the issue text.