Add support to client SSL PEM cert and key and root CA PEM cert

[elichai]

PR Info

Currently if you want to use SSL client certificate and key you can currently do it via a few options:

1. Manually create a PgPool or MySqlPool and create a DatabaseConnection.
2. For postgres:
   A. You can set sslrootcert=PATH, sslkey=PATH, sslca=PATH in the URI params.
   B. You can set env variables PGSSLCERT=PATH, PGSSLKEY=PATH, PGSSLROOTCERT=PATH
3. For mysql: You can set ssl-cert, ssl-key=PATH, ssl-ca=PATH in the URI params

Both 3 and 2 require you to mount the keys/certs to a volume and pass a PATH to that.
Only 1 allows you to pass the certs/keys themselves which allows nicer integrations with KMS/Secret Manager but comes at the cost of building the pools yourself,
Which is why I only added the _pem variants of sqlx