Support POSTing application-x-www-form-urlencoded Content-Type

[upgradingdave]

Description

Its currently not possible make a POST request and send data in the body with Content-Type of application/x-www-form-urlencoded.

The unqork api requires this and I think other folks can benefit from the ability as well.

The way I implemented this is that if there's a header set like this:

{
  "Content-Type": "application/x-www-form-urlencoded"
}

Then a body like this will be interpreted correctly:

{
  "grant_type":"password",
  "username":unqorkUsername,
  "password":unqorkPassword
}

Related issues

camunda-8-rest-connector-for-body-other-than-json