feat: Allow configuring the scheduler host on init

[acroca]

Description

Added a new flag for dapr init where the user can specify the scheduler host.

This allows running dapr apps pointing to a remote scheduler, as long as the configured scheduler host address is reachable from the dapr app.

To test this feature, I have a container with dind and dapr, where I executed:

dapr init --scheduler-override-broadcast-host-port dind-service

Then from another container with access to the docker instance from dind, I'm running a service with:

 dapr run --app-id=test \
                --metrics-port=9091 \
                --scheduler-host-address=dind-service:50006 \
                --placement-host-address=dind-service:50005 \
                --dapr-grpc-port 50001 \
                --app-port 50070 \
                --app-protocol grpc \
                --log-level debug \
                go run .

With this change, I see the following logs:

INFO[0000] Connected and received scheduler hosts addresses: [dind-service:50006]  app_id=test instance=7eb14174350b scope=dapr.runtime.scheduler.watchhosts type=log ver=1.15.6
DEBU[0000] Attempting to connect to Scheduler at address: dind-service:50006  app_id=test instance=7eb14174350b scope=dapr.runtime.scheduler.clients type=log ver=1.15.6
INFO[0000] Scheduler client initialized for address: dind-service:50006  app_id=test instance=7eb14174350b scope=dapr.runtime.scheduler.clients type=log ver=1.15.6
...
INFO[0002] Scheduler stream connected for [JOB_TARGET_TYPE_ACTOR_REMINDER]  app_id=test instance=7eb14174350b scope=dapr.runtime.scheduler.cluster type=log ver=1.15.6

Without this change, it failed:

INFO[0000] Connected and received scheduler hosts addresses: [localhost:50006]  app_id=test instance=7eb14174350b scope=dapr.runtime.scheduler.watchhosts type=log ver=1.15.6
DEBU[0000] Attempting to connect to Scheduler at address: localhost:50006  app_id=test instance=7eb14174350b scope=dapr.runtime.scheduler.clients type=log ver=1.15.6
INFO[0000] Scheduler client initialized for address: localhost:50006  app_id=test instance=7eb14174350b scope=dapr.runtime.scheduler.clients type=log ver=1.15.6
...
ERRO[0002] Failed to watch scheduler jobs, retrying: rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing: dial tcp [::1]:50006: connect: connection refused"  app_id=test instance=7eb14174350b scope=dapr.runtime.scheduler.cluster type=log ver=1.15.6

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Please reference the issue this PR will close: #1518

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[JoshVanL]

Let's also backport this to release-1.15 and create a patch release.

[acroca]

Patch PR here: #1521

[JoshVanL]

@acroca tests are failing

[msfussell]

@acroca - Please raise a PR for Dapr docs.

[acroca]

@acroca - Please raise a PR for Dapr docs.

@msfussell Thanks for reminding updating the docs :) dapr/docs#4721