Source/Destination Oracle: add option to provide custom TNS description

## Problem
When connecting to an oracle database, the current descriptor pattern as part of the JDBC-URL is not enough when dealing with failover scenario's or for instance mTLS connections requiring specific parameters which fail to parse when provided as additional JDBC-parameters.

Example: when connecting to an OCI hosted Autonomous database the following TNS-description is required;

```
description= (retry_count=20)(retry_delay=3)(address=(protocol=tcps)(port=1522)(host=someregion.oraclecloud.com))(connect_data=(service_name=someservicename.oraclecloud.com))
(security=
(MY_WALLET_DIRECTORY = /tmp/airbyte_local/somewalletdir)
(ssl_server_cert_dn="CN=someregion.oraclecloud.com, OU=Oracle ADB AMSTERDAM, O=Oracle Corporation, L=Redwood City, ST=California, C=US")
)
```
Currently there is no way to add extra security/failover options in the description.
Suggestion is to add an optional field for entry of a custom TNS name description.

## Description
In the web-GUI, on Oracle connections, an extra field is present allowing a custom TNS name description.