[espresso] add support for "-env" flag when used with espresso (Android) in saucectl #462

🚀 Feature Proposal

Currently saucectl doesn't support -env flag with espresso and xcuitests frameworks. It would be pretty handy if this feature would work with those frameworks.

Motivation

User could pass environment variables to Emulator and use them from espresso tests. (for example, for passing secret variables, passwords...)

Example

saucectl run -c ./.sauce/config.yml -e TEST_ENV=Hello
and then, I would be able to get the value of env variable from tests with System.getenv("TEST_ENV")