[High Priority] Build out all ROS Infrastructure

[SwapnilPande]

Which section of robot code is this for? ROS Infrastructure

Description of feature

• Define ROS topics and message types between all ROS Nodes (https://docs.google.com/spreadsheets/d/1IJqO0_JjhOKv841vDQbHhv6GSFOjP2CeG3pR-ihAOEE/edit?usp=sharing)
• Build any other necessary infrastructure for all nodes to communicate properly

[partlygloudy]

For the most part, the infrastructure will arise naturally as we write more nodes and start attempting to use them together. As long as nodes are written in the package that makes sense for it, there shouldn't be too much to do there. I think the most important thing here is that we define topic names somewhere + guidelines for naming new topics so people have a place to look when they aren't sure which name to use. We should also include global parameters there (for example arena dimensions, wheel diameter, other things that we don't want to hard code everywhere we use them)

[jasonlao99]

I started a Google Sheet where we'll keep track of ROS Topics, their Message Type, which nodes subscribe and publish to the topic, and brief description of the topic. I have linked the Sheet in Swapnil's top comment to this issue, and it can also be found under 'VUR 2018-2019 > Sub-Teams > Programming > Documentation' in Google Drive.

I'll be filling this out over the next coming week or so. Anyone can feel free to additions or changes to it.