pydrake: Develop more Pythonic and user-friendly components

[EricCousineau-TRI]

My present goal for pydrake is to provide Python wrappings of C++ Drake, prioritizing keeping the same API as C++, as I myself do not want to spend time at the moment developing a brand new API, and would prefer to use pydrake to prototype C++ behavior that, if it under performs in Python, can be more easily translated back to C++ given that the APIs are relatively similar.

At some point, it would be convenient to provide a Python API that is truer to Python, and is more user-friendly. Some goals:

• More Pythonic in naming / API. Current naming conventions for C++ functionality stays true to C++ conventions; any new attributes / features (e.g. the Image[PixelType].data property) are written to be Pythonic (still not sure if that's a good thing...)
• Reduce the type-specific hoops needed for working with the Systems framework (e.g. creating an RgbdCamera and querying images)
• Other things...

(There were some discussions on slack about this, but since this came up in #8585 , wanted to make sure it's captured in an issue.)

\cc @thduynguyen @ggould-tri @peteflorence

[EricCousineau-TRI]

I think this is too broad of an issue. Closing for now.