[BUG] New agent memory option MySQL and Postgres creating multiples connections to database

[joaopaulo-m]

Describe the bug
On version 2.1.4 was added Postgres and MySql options to Agent Memory node. It works fine but after a few messages starts getting the "Too many connections errors" and my database has 29 connections.

To Reproduce
Steps to reproduce the behavior:

1. Create a agent flow
2. Add a Agent Memory with Postgres or MySQL option
3. Send a few messages
4. Check the database connections number

Expected behavior
Create a singleton of the TypeOrm DataSource, I checked the project code and I found that its been created a new instance of TypeOrm DataSource every time a MySqlSaver or PostgresSave it's created, this might be the problem.

Screenshots