Repo documentation

[tjkirch]

These are the basic docs we'd like before launch:

• README.md - basic overview, link to more specific docs
• INSTALL.md - image build process, and setup process to use Thar with EKS
• workspaces/api/README.md - the API system - its components and how they work together
• workspaces/api/migration/README.md - the migration system
• workspaces/api/migration/migrator/README.md - the migrator (using cargo-readme)
• workspaces/updater/README.md - the update system
• packages/README.md - the packaging process
• extras/dogswatch/README.md - update operator

[tjkirch]

API system: #200
migrator: #201
migration system: #202
INSTALL: #203

[tjkirch]

I'm hoping @iliana can write or delegate the updater README.

I'm hoping @bcressey can write or delegate the packaging README - perhaps after the changes he's working on are settled, since they'll affect the process.

I'm hoping @jahkeup can write or delegate the README for the update operator.

I'm working on the root-level README.

[bcressey]

I will write the README for packages & images.

[sam-aws]

Currently writing up some things for updater/

[tjkirch]

Updater: #381