Use tokio broadcast::channel

[rafaeling]

Issue -> #60

[codecov]

Codecov Report

Attention: Patch coverage is 52.63158% with 36 lines in your changes missing coverage. Please review.

Project coverage is 59.61%. Comparing base (5604aa9) to head (a89dc6e).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
databroker/src/grpc/kuksa_val_v2/val.rs	43.75%	18 Missing ⚠️
databroker/src/broker.rs	70.27%	11 Missing ⚠️
databroker/src/grpc/kuksa_val_v1/val.rs	0.00%	5 Missing ⚠️
databroker/src/viss/v2/server.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #95      +/-   ##
==========================================
- Coverage   59.71%   59.61%   -0.11%     
==========================================
  Files          33       33              
  Lines       15906    15955      +49     
==========================================
+ Hits         9499     9512      +13     
- Misses       6407     6443      +36     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[erikbosch]

Do not know how much it says, but I did a smoke test with a subscription with kuksa-client and it worked without problem.