Support for sslmode no-verify

**Is your feature request related to a problem? Please describe.**

When connecting to a remote database that is not exposed to the internet using SSH tunnels, the self-signed CA will not match the servers certificate name as for the connecting client the server name would be "localhost".

**Describe the solution you'd like**

Since the server is trusted and we just need a secure connection from the client, please support `no-verify` as a valid option for the `sslmode` option.

Currently if we try using `no-verify` option the following error is thrown

```shell
ConnectionParamsError: Supplied DSN has invalid sslmode 'no-verify'
```

**Additional context**

This is especially painful when the servers are hosted on AWS RDS (Postgres) and there is a requirement for connecting to them using the postgres client.

The servers certificate will have the certificate issued for the fully qualified name and when connecting over SSH tunnel and using `localhost` as the host name we receive error

```shell
TLS connection failed with message: invalid peer certificate: NotValidForName
```

Start by locating the DSN sslmode validation that emits the invalid-option error, then trace how the TLS connection handles certificate-name verification. Confirm the accepted option is handled consistently, and verify that a tunneled PostgreSQL connection no longer rejects it while existing sslmode behavior remains unchanged.

Written by the indexing model from the issue text.