Web UI fails to parse password with "\"

(tested with postgres instance)

If the postgres user password contains a "\" the login fails.

Looking at the JSON payload, the "\" is escaped correctly:

```json
{
"Driver": "postgres",
"IsSharded": false,
"Host": "x.x.x.x",
"Port": "5432",
"Database": "pgbench",
"User": "postgres",
"Password": "XXX\\XXXXX",
"Dialect": "postgresql",
"DataCenter": ""
}
```
I guess that it is either decoded incorrectly or re-encoded incorrectly when sent to Postgres.