Implement SQLAlchemy integration and create database schemas for local and remote modes; refactor KomCache class methods

src/komcache/schemas/sqlite.py

@@ -0,0 +1,20 @@
+CREATE_SQLITE_TABLES = ["""
+CREATE TABLE IF NOT EXISTS manga_requests (
+id INTEGER PRIMARY KEY AUTOINCREMENT,
+manga_id INTEGER,
+grabbed BOOLEAN DEFAULT 0);""","""CREATE TABLE IF NOT EXISTS komgrabber (
+id INTEGER PRIMARY KEY AUTOINCREMENT,
+name TEXT NOT NULL,
+series_id TEXT NOT NULL, 
+status TEXT NOT NULL,
+created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+last_checked TIMESTAMP DEFAULT 0,
+completed BOOLEAN DEFAULT 0);""","""CREATE TABLE IF NOT EXISTS komtagger (
+id INTEGER PRIMARY KEY AUTOINCREMENT,
+series_id TEXT NOT NULL,
+title TEXT NOT NULL,
+updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+last_checked TIMESTAMP DEFAULT 0,
+status TEXT NOT NULL);
+"""]