Subscription-APIs: Alignment of errors with Commonalities

[maxl2287]

What type of PR is this?

Add one of the following kinds:

• enhancement/feature

What this PR does / why we need it:

Alignement of errors according to Commonalities guideline.

Which issue(s) this PR fixes:

Fixes #184

Changelog input

 release-note

- Aligned error scenarios list with Commonalities for subscription APIs

[bigludo7]

Max, I've only review code/API_definitions/device-reachability-status-subscriptions.yaml and got a couple of comments for your consideration:

• Probably 2 422 examples are missing
• not sure why we should not remove 429 as it is part of the template finnally

Same comment should apply for device-roaming-status-subscriptions.yaml

[maxl2287]

@bigludo7 updates are done.
Please review again :)

[bigludo7]

LGTM :)
Thanks Max.

[akoshunyadi]

I've noticed that there are quite a lot of differences to the template. Which has already differences to the design guidelines. :-)
Which means at the end, that we don't have standardized subscriptions in Camara.
Should we merge this PR as it is and create another one for the RC2 to match with the template, or keep it open for the RC2?

Btw. the last change of the template will be released in RC2 of the Commonalities Release, so currently we are conform with the RC1.

[akoshunyadi]

As discussed, regarding the error codes we should make one more round about the subscription template + implementations. For the RC1 it LGTM