Update examples to execute from the root of the repo

Description

Update top-level examples and Triton start-up commands to execute from the root of the repo
Where possible set default values for cli flags, removing the need to set them for the common use-case
Where possible remove the need for defining MORPHEUS_ROOT
Ensure C++ Triton pipelines use port 8000 to avoid the warning about the grpc port.
Optionally cast types in the C++ impl of the Triton stage when force_convert_inputs=true and the input and model types didn't match (previously types were always casted)
Remove --num_threads=1 restriction and configure logging for the log_parsing example
Remove --num_threads=8 restriction from nlp_si_detection since the pipeline has more than 8 stages.
Don't invoke the C++ impl of preallocate if the type being requested isn't supported on the C++ side (strings)
Don't use the C++ impl of the Triton stage if use_shared_memory is requested as this isn't supported in C++.
Add missing gnn-fraud-classification stage to CLI alternative for gnn_fraud_detection_pipeline example

Closes #1671

I am familiar with the Contributing Guidelines.
When the PR is ready for review, new or existing tests cover these changes.
When the PR is ready for review, the documentation is up to date with these changes.