docs(adr): adr template, design principles adr (#26)

## Description

We need a more directed approach to `go-cuckoo`'s interface.
This ADR proposes that direction.

## Changes

- Add ADR template.
- Add "Adopt Congruent and Familiar Design For `go-cuckoo`" ADR.

## Design Decisions

- ~~Put ADRs under `adr/` for more. Because we don't realy have any docs right now, it doesn't make much sense to nest it.~~

## Checklist

- [x] Tests pass
- [x] Docs updated

Reviewed-on: #26
Co-authored-by: M.V. Hutz <git@maximhutz.me>
Co-committed-by: M.V. Hutz <git@maximhutz.me>

docs/adr/000_template.md

@@ -0,0 +1,15 @@
+# Title
+
+**Status**: <!-- Proposed, accepted, rejected, etc... -->
+
+## Context
+
+<!-- What is the issue that we're seeing that is motivating this decision or change? -->
+
+## Decision
+
+<!-- What is the change that we're proposing and/or doing? -->
+
+## Consequences
+
+<!-- What becomes easier or more difficult to do because of this change? -->