feat(consent-tester): Phase B — named CMP library + plugin architecture

cmp_extractor.py refactored to thin coordinator (123 LOC, was 223).
Discovers all CMP modules via cmp_library/_registry.py:load_all() at
import time. Restart consent-tester to pick up new modules.

New cmp_library/ folder:
- _registry.py: auto-discovers all modules with MATCHER + reconstruct()
- epaas.py:     BMW Group ePaaS (extracted from cmp_extractor)
- onetrust.py:  cdn.cookielaw.org Groups/Cookies schema
- cookiebot.py: consent.cookiebot.com Categories schema
- usercentrics.py: api.usercentrics.eu services schema
- didomi.py:    sdk.privacy-center.org notice + vendors + purposes
- trustarc.py:  consent.trustarc.com categories + vendors

Each module:
- MATCHER: re.Pattern matching the CMP JSON endpoint URL
- reconstruct(d: dict) -> str: builds German Markdown cookie-policy text

Phase E (self-improving) will write auto_*.py files into the same folder;
_registry already picks those up via pkgutil.iter_modules.

consent-tester/services/cmp_library/__init__.py

@@ -0,0 +1 @@
+"""Named CMP library — one module per platform, loaded by _registry.py."""