Support passing in feature_store.yaml explicitly to FeatureStore

[achals]

Is your feature request related to a problem? Please describe.
Right now, feast assumes that the feature_store.yaml is always located at the root of the feature repo. This is a reasonable assumption, but introduces some issues for users - when using multiple environments (e.g. staging vs production) users need to duplicate their feature definitions into multiple directories.

Describe the solution you'd like
The feast CLI should support a new flag on all commands, the explicit location of the feature_store.yaml file. Something like:

feast --config-yaml-location production/feature_store.yaml apply

Similarly, the FeatureStore class should have an additional parameter, config_yaml_location (or something like it):

class FeatureStore:
    def __init__(
        self, repo_path = None, config_yaml_location = None
    ):

        config_path = config_yaml_location or Path(repo_path) / 'feature_store.yaml'

Describe alternatives you've considered
?

[kevjumba]

This is a duplicate issue @achals from #1556