feat: Add all 9 data source extractors for football statistics

Created comprehensive data extraction framework with extractors for:
- FBref: 44 tables (team/player season & match stats, events, shots)
- FotMob: 11 tables (league table, schedule, 7 match stat types)
- Understat: 7 tables (xG metrics, shot coordinates, PPDA)
- WhoScored: 4 tables (Opta event stream, schedule)
- Sofascore: 4 tables (standings, schedule)
- ESPN: 3 tables (schedule, matchsheet, lineups)
- ClubElo: 2 tables (ELO ratings by date, team history)
- MatchHistory: 1 table (betting odds from 13+ bookmakers)
- SoFIFA: 6 tables (EA Sports FC player/team ratings)

Each extractor:
- Extends BaseExtractor abstract class
- Implements table configs and extraction methods
- Handles data validation and DataFrame conversion
- Provides error handling for missing data
- Supports UPSERT operations via conflict columns

Total: 82+ tables across all data sources

Author: claude

scripts/extractors/__init__.py

@@ -0,0 +1,28 @@
+"""
+Data Source Extractors
+Extracts data from various football statistics sources
+"""
+
+from .base_extractor import BaseExtractor
+from .fbref_extractor import FBrefExtractor
+from .fotmob_extractor import FotMobExtractor
+from .understat_extractor import UnderstatExtractor
+from .whoscored_extractor import WhoScoredExtractor
+from .sofascore_extractor import SofascoreExtractor
+from .espn_extractor import ESPNExtractor
+from .clubelo_extractor import ClubEloExtractor
+from .matchhistory_extractor import MatchHistoryExtractor
+from .sofifa_extractor import SoFIFAExtractor
+
+__all__ = [
+    'BaseExtractor',
+    'FBrefExtractor',
+    'FotMobExtractor',
+    'UnderstatExtractor',
+    'WhoScoredExtractor',
+    'SofascoreExtractor',
+    'ESPNExtractor',
+    'ClubEloExtractor',
+    'MatchHistoryExtractor',
+    'SoFIFAExtractor',
+]