feat(tfstated): implement GET and POST methods, states are encrypted in a sqlite3 database

pkg/database/sql/000_init.sql

@@ -0,0 +1,10 @@
+CREATE TABLE schema_version (
+  version INTEGER NOT NULL
+) STRICT;
+
+CREATE TABLE states (
+  id INTEGER PRIMARY KEY,
+  name TEXT NOT NULL,
+  data BLOB NOT NULL
+) STRICT;
+CREATE UNIQUE INDEX states_name on states(name);