Added support for http proxy

[vivetiwa]

Summary

Added support for http proxy to the connector configuration. This allows the user to add proxy host details when using the connector within a corporate environment having proxy host.

Related Issue

26

Changes

Added support for http proxy with the following connector configuration

• aep.connection.proxy.host: address of the proxy host to connect through
• aep.connection.proxy.port: port of the proxy host to connect through
• aep.connection.proxy.user: username for the proxy host
• aep.connection.proxy.password: password for the proxy host

Relevant Documentation

DEVELOPER_GUIDE.md

How Has This Been Tested?

• Added a new test case aepSinkConnectorTestViaProxy() to the existing test suite. To execute this test case, have setup a new mock extention wiremockExtensionViaProxy which acts as a proxy server to redirect the request to the actual wiremockExtension.
• Test locally by using local proxy server and pointing to AEP endpoint

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• [x] I have signed the Adobe Open Source CLA.
• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.