chore: adopt the NAPALM driver standard

- CI arrives in .gitea/workflows/ci.yml and calls the shared driver
  workflow of NAPALM/driver-standard; the repo had none before.
- setuptools>=77 and the SPDX license string PEP 639 wants, without the
  License classifier; napalm-device-types>=4.21.1 from PyPI; Issues and
  Changelog links on git.netork.io. LICENSE, NOTICE and py.typed were
  already there and stay.
- The test extra becomes the dev extra of the standard, plus responses,
  which the tests mock AMT with.
- mypy strict with the untyped imports (napalm, requests, defusedxml)
  named instead of ignored globally; napalm_amt.driver is exempt for now
  (5 errors: getters return dicts where the role declares TypedDicts),
  recorded in tests/quality_baseline.json with get_event_log's
  complexity of 11.
- Coverage floor 95 % (measured 95.87 %).
- CHANGELOG.md in Keep a Changelog form; the README's development steps
  install from PyPI.

.gitea/workflows/ci.yml

@@ -0,0 +1,15 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+    tags: ["v*"]
+  pull_request:
+
+jobs:
+  driver:
+    uses: NAPALM/driver-standard/.gitea/workflows/driver.yml@main
+    with:
+      standard-ref: main
+    secrets:
+      PYPI_TOKEN: ${{ secrets.PYPI_TOKEN }}