removing cruft; switch CoC to match valkey-io/valkey

[stockholmux]

Description

• Removes some non-relevant template cruft
• Moves CoC from dummy text to Contributor Covenant to match valkey-io/valkey

Issues Resolved

n/a

Check List

• [x] Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the BSD-3-Clause License.

[stockholmux]

Humm. Merging is blocked "The base branch requires all commits to be signed" but both commits are signed and DCO bot seems to be successful.

Do we need to manually re-run the check?

[daniel-house]

It appears to be asking for a "signature", not a "sign-off".