Proposal for an improved project structure.

Note: this deprecates the fine-grained, high-overlap cascading MAINTAINERS files,
and replaces them with a single top-level file, using a new structure:

* More coarse grained subsystems with dedicated teams of maintainers
* Core maintainers with a better-defined role and a wider scope (if it's
not in a subsystem, it's up to the core maintainers to figure it out)
* Architects
* Operators

This is work in progress, the goal is to start a conversation

Signed-off-by: Solomon Hykes <solomon@docker.com>
Link to project/ directory from README

Signed-off-by: Solomon Hykes <solomon@docker.com>