This PR makes OnCall compatible with chatops-proxy v3. When CHATOPS_V3
is enabled, oncall will use new api client to register tenants and slack
installations. Also I added v3 routes for slack and telegram, so it's
possible to test new chatops proxy.
Currently two versions of chatops-proxy api are deployed, but they are
not compatible. They are doing same thing, using different db model and
tables. Once only v3 version will be left in prod, I'll remove
CHATOPS_V3 env var, all leftovers of previous api client and v3 slack
and telegram routes.
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Co-authored-by: Vadim Stepanov <vadimkerr@gmail.com>
