refactor: ad a Database class and clean deletewallet view

LNbits/db.py

@@ -0,0 +1,30 @@
+import os
+import sqlite3
+
+
+LNBITS_PATH = os.path.dirname(os.path.realpath(__file__))
+DEFAULT_PATH = os.path.join(LNBITS_PATH, "data", "database.sqlite3")
+
+
+class Database:
+    def __init__(self, db_path: str = DEFAULT_PATH):
+        self.path = db_path
+        self.connection = sqlite3.connect(db_path)
+        self.cursor = self.connection.cursor()
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.cursor.close()
+        self.connection.close()
+
+    def fetchall(self, query: str, values: tuple) -> list:
+        """Given a query, return cursor.fetchall() rows."""
+        self.cursor.execute(query, values)
+        return self.cursor.fetchall()
+
+    def execute(self, query: str, values: tuple) -> None:
+        """Given a query, cursor.execute() it."""
+        self.cursor.execute(query, values)
+        self.connection.commit()