[FEATURE] read Gradle properties from DHF project

[crism]

Is your feature request related to a problem? Please describe.
Given a fully-configured DHF project, it would make sense for HCCE to read the settings from the already-tested configuration, as Hub Central does.

What is the user-facing scenario that prompted this gap in functionality?
Any DHF project with non-default settings, such as non-digest authentication or use of SSL, means that HCCE will not run without explicit settings in application.properties. It was not clear that this is the case, and a lot of time was wasted trying to get HCCE to run in such a setting.

Describe the solution you'd like
When initializing the hubProject, HCCE should look for existing properties files based on the -DdhfDir and -DdhfEnv switches, with defaults (current directory and local). It should consume those properties files, applying overrides from application.properties.

Describe alternatives you've considered
The alternative (and current workaround) is to redundantly specify all of those properties explicitly in application.properties. This runs the risk of divergence.