Add support for GEE service account credentials

[kevinlacaille]

Is your feature request related to a problem? Please describe.
In order for a user to bring their own GCS service account, we must supply them with somewhere to input that SA's credentials in
order_request.google_earth_engine()

We already show support for the credentials field on our Dev Center's example request JSON.

Describe the solution you'd like
Current Google Earth Engine configuration:

def google_earth_engine(project: str, collection: str) -> dict:
    '''Google Earth Engine configuration.
    Parameters:
        project: GEE project name.
        collection: GEE Image Collection name.
    '''
    cloud_details = {
        'project': project,
        'collection': collection,
    }
    return {'google_earth_engine': cloud_details}

Proposed solution:

def google_earth_engine(project: str, collection: str, credentials: str) -> dict:
    '''Google Earth Engine configuration.
    Parameters:
        project: GEE project name.
        collection: GEE Image Collection name.
        credentials: Base64-encoded credentials for the GEE service account
    '''
    cloud_details = {
        'project': project,
        'collection': collection,
        'credentials': credentials,
    }
    return {'google_earth_engine': cloud_details}

Current test:

def test_google_earth_engine():
    gee_config = order_request.google_earth_engine('project', 'collection')
    expected = {
        'google_earth_engine': {
            'project': 'project',
            'collection': 'collection',
        }
    }

    assert gee_config == expected

Proposed test:

def test_google_earth_engine():
    gee_config = order_request.google_earth_engine('project', 'collection', 'credentials')
    expected = {
        'google_earth_engine': {
            'project': 'project',
            'collection': 'collection',
            'credentials': '<REDACTED>',
        }
    }

    assert gee_config == expected

Additional context
Many users like to bring their own service account over using Planet's, so this feature is likely to be used.

[strixcuriosus]

Note: bringing your own service account for GEE delivery is recommended for high volume workloads.

With the default Planet Service Account, the ingest queue can fill up with large orders. Planet recommends a limit of approximately 1000 assets delivered per organization, per day. There is also an option to bring their own service account for a dedicated queue with greater scalability.

See these docs for more info:
https://developers.planet.com/docs/integrations/gee/faq/
https://developers.planet.com/docs/integrations/gee/delivery/#creating-a-service-account

[strixcuriosus]

Any thoughts on how the CLI UX could encourage and/or inform users of this option?