Connection quality feature

[kalombos]

We need add to callback to PoolBackend to check connection like in pyscopg3

Some useful snippets:

psycopg3 check connection method:

@staticmethod
    def check_connection(conn: CT) -> None:
        """
        A simple check to verify that a connection is still working.

        Return quietly if the connection is still working, otherwise raise
        an exception.

        Used internally by `check()`, but also available for client usage,
        for instance as `!check` callback when a pool is created.
        """
        if conn.autocommit:
            conn.execute("")
        else:
            conn.autocommit = True
            try:
                conn.execute("")
            finally:
                conn.autocommit = False

Some implementation of healthcheck for peewee-async

class CheckPoolBackend(PoolBackend):
    async def acquire(self):
        while True:
            conn = await super().acquire()
            try:
                await conn.execute("Select 1") # our healtcheck query
            except Exception:
                conn.close()
                self.release(conn)
            else:
                return conn
            # https://github.com/psycopg/psycopg/blob/master/psycopg_pool/psycopg_pool/pool.py#L220
            # AttemptWithBackoff