feat: Implement consumer handler in the Simulator

[georgi-l95]

Description:
This pull request aims to make use of the consumer mode in the simulator, by adding needed implementations.
We add:

• gRPC client and observer for consuming blocks, which utilizes SubscribeStreamRequest and SubscribeStreamResponse, which are part of the subscribeBlockStream rpc.
• Makes the neccessery changes to initilize managers and clients, depending on mode.
• Adds neccessery unit and integration tests for sufficient code coverage, by making use of as less mocks as possible.

Related issue(s):

Fixes #121

Notes for reviewer:

Checklist

• Documented (Code comments, README, etc.)
• Tested (unit, integration, etc.)

[mattp-swirldslabs]

I left a few suggestions

[ata-nas]

@georgi-l95 generally looks good on my first pass! It is nice to see a clear distinction of different components.

I do have some comments left here and there.

Also, please consider to write javadocs for the tests, since it is not possible to see what is the intent of the test and it is very hard to review them.

[ata-nas]

Looks good @georgi-l95 !

[mattp-swirldslabs]

Looks good

[codecov]

Codecov Report

Attention: Patch coverage is 99.01961% with 1 line in your changes missing coverage. Please review.

Project coverage is 96.96%. Comparing base (a278936) to head (40aca65).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
.../block/simulator/generator/BlockStreamManager.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #360      +/-   ##
============================================
- Coverage     97.23%   96.96%   -0.27%     
- Complexity      375      395      +20     
============================================
  Files            76       79       +3     
  Lines          1338     1417      +79     
  Branches         91       93       +2     
============================================
+ Hits           1301     1374      +73     
- Misses           28       32       +4     
- Partials          9       11       +2     

Files with missing lines	Coverage Δ
...a/com/hedera/block/common/utils/Preconditions.java	100.00% <100.00%> (ø)
...edera/block/simulator/BlockStreamSimulatorApp.java	80.43% <100.00%> (+3.83%)	⬆️
...ulator/generator/BlockAsDirBlockStreamManager.java	100.00% <100.00%> (ø)
...lator/generator/BlockAsFileBlockStreamManager.java	90.90% <100.00%> (-9.10%)	⬇️
...dera/block/simulator/grpc/GrpcInjectionModule.java	0.00% <ø> (ø)
...ulator/grpc/impl/ConsumerStreamGrpcClientImpl.java	100.00% <100.00%> (ø)
...ck/simulator/grpc/impl/ConsumerStreamObserver.java	100.00% <100.00%> (ø)
...mulator/grpc/impl/PublishStreamGrpcClientImpl.java	90.38% <100.00%> (ø)
...ock/simulator/grpc/impl/PublishStreamObserver.java	100.00% <100.00%> (ø)
.../block/simulator/metrics/SimulatorMetricTypes.java	100.00% <100.00%> (ø)
... and 4 more