Extend configuration options, update dependencies, extend tests

• Add support to specify module import generator
• Add support for runtimeVars
• Allow to exclude runtime
• Set proper context for template loading
• Add mocha unit tests
• Improve documentation
• Bump @adobe/htlengine to v4
• Add prettier and format code

Thanks a lot to @tripodsan for doing the heavy lifting.

v1.1.0...v2.0.0