Opt-in setting to receive notifications when patches change status

[dlespiau]

https://bugzilla.yoctoproject.org/show_bug.cgi?id=7684

The way to opt-in would be to add oneself to the CC list of this series. A user subscribed to the CC list of a series would be alerted of activity.

A few notes:

• this needs to be a bit smart so we avoid flooding people with too many emails (ie don't send a mail per patch status change, but collapse several changes into one mail).
• is the patch submitter part of that Cc list by default?
• still need a global option, per-user, (and per project?), to disable notifications

[belenbarrospena]

Note to self: Issue #66 seems cover this for series, but I guess if a patch is not part of a series, you might also want to subscribe to its cc list.

[dlespiau]

huum, I think you are right and the way to opt-in would be to be part of that CC list. As we said earlier, a single patch is part of a series of one patch, so it'll still work. Let's close #66 and amend this issue then.