Build API that accepts yaml file instead of yaml string

[vizsatiz]

Is your feature request related to a problem? Please describe.
Right now someone has to write the yaml file reading logic to create agents. If there were ways to directly pass the yaml file, it would have been easier

Describe the solution you'd like
The build API directly accepting yaml as a file path

[vizsatiz]

Make a change to the Flo.build API to accept an optional parameter named yaml_path= which can take in yaml file path and use it. (inside core.py)

Flo.build(session, yaml_path="<path to yaml>")

[vizsatiz]

Fix in #73

[vizsatiz]

Closed in #73