Rework Intro of External Interfaces Chapter / Possibly Rename

[schulzm]

Problem

After removal of threads discussion from the EI chapter, the chapter focuses on a single thing: generalized requests.

Proposal

Rework introduction text, possible remove it. We may also want to rename the chapter into "Generalized Requests"

Changes to the Text

tbd.

Impact on Implementations

None

Impact on Users

Easier way to find Generalized Requests in the standard

References

n/a

[schulzm]

I have created a PR that implements the suggestion above and renames the chapter from EI to Generalized requests. To the chapter committee: please check the implementation of this change (which is intentionally kept minimal). The other (bigger) question is whether we actually want to do this (I see pros and cons - makes sense at the moment, but there may be more EI interfaces in the future). We should bring this to the whole forum in December.