feat: Add ent-based sqlite3 storage

Signed-off-by: m.nabokikh <maksim.nabokikh@flant.com>

storage/ent/schema/devicerequest.go

@@ -0,0 +1,50 @@
+package schema
+
+import (
+	"github.com/facebook/ent"
+	"github.com/facebook/ent/schema/field"
+)
+
+/* Original SQL table:
+create table device_request
+(
+    user_code     text      not null  primary key,
+    device_code   text      not null,
+    client_id     text      not null,
+    client_secret text,
+    scopes        blob      not null,
+    expiry        timestamp not null
+);
+*/
+
+// DeviceRequest holds the schema definition for the DeviceRequest entity.
+type DeviceRequest struct {
+	ent.Schema
+}
+
+// Fields of the DeviceRequest.
+func (DeviceRequest) Fields() []ent.Field {
+	return []ent.Field{
+		field.Text("user_code").
+			SchemaType(textSchema).
+			NotEmpty().
+			Unique(),
+		field.Text("device_code").
+			SchemaType(textSchema).
+			NotEmpty(),
+		field.Text("client_id").
+			SchemaType(textSchema).
+			NotEmpty(),
+		field.Text("client_secret").
+			SchemaType(textSchema).
+			NotEmpty(),
+		field.JSON("scopes", []string{}).
+			Optional(),
+		field.Time("expiry"),
+	}
+}
+
+// Edges of the DeviceRequest.
+func (DeviceRequest) Edges() []ent.Edge {
+	return []ent.Edge{}
+}