In order to make decisions about the code and the design explicit and easier
to reference in future we want to record significant architectural decisions.
This commit introduces docs/adr with a template Architectural Decision Record
and index using the [MADR](https://adr.github.io/madr/) format.
It also adds ADR 0000 to document the decisions to use MADR.
Fixes#1141
Signed-off-by: Joshua Lock <jlock@vmware.com>
