refactor(uuid): specify the stream node uuid when using grpc connection

[rgallor]

Use EVN ASTARTE_MSGHUB_NODE_ID or the toml file to specify the node id of the stream application

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 12 lines in your changes missing coverage. Please review.

Project coverage is 4.8%. Comparing base (ac9f8de) to head (1f71c48).
Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
src/astarte.rs	0.0%	12 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
src/astarte.rs	8.7% <0.0%> (-1.2%)	⬇️