Simplify the process of consuming the in-vehicle stack interfaces

[ladatz]

Simplify the process of consuming the in-vehicle stack interfaces from sample workloads. During the hackathon, some participants had trouble including the in-vehicle stack interfaces (in this case, proto files) in their dockerfiles during development.

Some suggested improvements include:

• Restructuring the directory structure and mount points for easier development (this will be addressed in a separate issue Restructure folder structure of maestro (improve mount points for easier development) #3 more broadly, but it can be related to this issue)
• Have official "releases" of the in-vehicle stack components including the interfaces, so that they can easily be downloaded according to the release tag as a public api and included in the dockerfile for easier development