Add ADR for build tool

[emmyoop]

resolves dbt-labs/dbt-adapters#3

Description

This is just the adr to make it more clear. #21 will follow with more complete hatch implementation.

Checklist

• I have read the contributing guide and understand what's expected of me
• I have signed the CLA
• I have run this code in development and it appears to resolve the stated issue
• I have opened an issue to add/update docs, or docs changes are not required/relevant for this PR
• I have run changie new to create a changelog entry

[martynydbt]

Having only one maintainer is pretty high risk.
How much effort does it take to switch between tools should it become abandonware?

[emmyoop]

@martynydbt while it only has 1 maintainer it is actually part of the Python Packaging Authority (PyPA) and lives in the PyPA org in GitHub. PyPA is a working group that maintains a core set of software projects used in Python packaging. it also has had 69 contributors over its lifetime. I can add this color to the doc.

[aranke]

Discussed offline, LGTM.