Reconsider alertmanager interface name

[mmanciop]

alertmanager is not a general relation name, it is more the interface of the relation. We need to find a more general name and use it as standard name for relations like "we push alerts".

[balbirthomas]

@sed-i May I request you to pick this up as part of you refactor of the Alertmanager Charm library. Feel free to discuss suitable names on channel and with @mmanciop .

[sed-i]

@mmanciop, in alertmanager I called it alerting. How about that?

Currently:
https://github.com/canonical/prometheus-operator/blob/0e412c999b3b555e7cb0e4de102452e10a111168/metadata.yaml#L31-L35

[balbirthomas]

ATTN: @dstathis

[mmanciop]

edited for clarity:

We need to keep the relation interface unambiguous with:

• other charms that receive alerts
• other relation names that alertmanager may expose, see, e.g., the Karma ones

IMO, let’s call it alertmanager_dispatch