refactor: remove databases from code an use schemas instead

All databases are now saved together in the same LNBITS_DATA_FOLDER.
Extensions have to define a schema.yml file for creating the necessary database.

lnbits/data/schema.sql

@@ -1,39 +1,47 @@
 CREATE TABLE IF NOT EXISTS accounts (
-    id text PRIMARY KEY,
-    email text,
-    pass text
+    id TEXT PRIMARY KEY,
+    email TEXT,
+    pass TEXT
+);
+
+CREATE TABLE IF NOT EXISTS extensions (
+    user TEXT NOT NULL,
+    extension TEXT NOT NULL,
+    active BOOLEAN DEFAULT 0,
+
+    UNIQUE (user, extension)
 );
 
 CREATE TABLE IF NOT EXISTS wallets (
-    id text PRIMARY KEY,
-    name text NOT NULL,
-    user text NOT NULL,
-    adminkey text NOT NULL,
-    inkey text
+    id TEXT PRIMARY KEY,
+    name TEXT NOT NULL,
+    user TEXT NOT NULL,
+    adminkey TEXT NOT NULL,
+    inkey TEXT
 );
 
 CREATE TABLE IF NOT EXISTS apipayments (
-    payhash text NOT NULL,
-    amount integer NOT NULL,
-    fee integer NOT NULL DEFAULT 0,
-    wallet text NOT NULL,
-    pending boolean NOT NULL,
-    memo text,
-    time timestamp NOT NULL DEFAULT (strftime('%s', 'now')),
+    payhash TEXT NOT NULL,
+    amount INTEGER NOT NULL,
+    fee INTEGER NOT NULL DEFAULT 0,
+    wallet TEXT NOT NULL,
+    pending BOOLEAN NOT NULL,
+    memo TEXT,
+    time TIMESTAMP NOT NULL DEFAULT (strftime('%s', 'now')),
 
     UNIQUE (wallet, payhash)
 );
 
 CREATE VIEW IF NOT EXISTS balances AS
-  SELECT wallet, coalesce(sum(s), 0) AS balance FROM (
-      SELECT wallet, sum(amount) AS s -- incoming
+  SELECT wallet, COALESCE(SUM(s), 0) AS balance FROM (
+      SELECT wallet, SUM(amount) AS s  -- incoming
       FROM apipayments
-      WHERE amount > 0 AND pending = 0 -- don't sum pending
+      WHERE amount > 0 AND pending = 0  -- don't sum pending
       GROUP BY wallet
     UNION ALL
-      SELECT wallet, sum(amount + fee) AS s -- outgoing, sum fees
+      SELECT wallet, SUM(amount + fee) AS s  -- outgoing, sum fees
       FROM apipayments
-      WHERE amount < 0 -- do sum pending
+      WHERE amount < 0  -- do sum pending
       GROUP BY wallet
   )
   GROUP BY wallet;