Clean export environment variables

[prasadtalasila]

Description

We need clean export of environment variables to node.js processes. The need arose because of the following hiccup:

During functional tests, it was observed that nyc can't wait for a long time (>60 seconds) to collect the coverage data. Hence, we needed to go for incremental code coverage report generation. Such a step requires that we start and stop the AutolabJS components for each functional test. Since we perform bash shell export of environment variables, we end up with lot of unnecessary exported variables over a sequence of tests. We need a guarantee of clean environment for each of the node.js processes.

One way to achieve the clean environment is to use dotenv node.js package to provide the environment variables. The environment variables are to be kept in deploy/configs/env directory.

Steps to Reproduce

1. code coverage reporting of functional tests

Expected behavior: [What you expect to happen]
Code coverage reporting works

Actual behavior: [What actually happens]
Code coverage report does not report properly for functional tests.

Reproduces how often: [What percentage of the time does it reproduce?]
Every time functional tests are run.

[prasadtalasila]

Use rc module for reading the configs in all the AutolabJS components.