Clarify Discovery API scope

[zolkis]

As discussed in the Discovery TF call on 24.2.2020, the scope of the Scripting API for discovery needs some clarifications vs device lifecycle, discussed in Architecture TF.

There are several types of discovery:

1. discovery during onboarding/provisioning (e.g. of unowned devices)
2. discovery of Thing directories, during provisioning or in operational mode
3. discovery of Things (when in operational mode).

The current API has been designed with 3. in mind, but could be adapted to be used also for 1. and 2.

Related issues:
w3c/wot-discovery#2
w3c/wot-architecture#48
https://github.com/w3c/wot-architecture/issues/425
See also:
Device lifecycle comparisons
WoT Device Lifecycle working draft

[danielpeintner]

Note: I suggest to remove the F2F label and re-label it with discovery

[JKRhb]

Although the Discovery aspects have been improved, I suppose some clarifications could still be added to the specification?

[relu91]

Call 29/01:

• @zolkis needs to review the issue and close it if needed. We are waiting for his review.