Import flow: Move advanced option target port above the advanced routing options

Description

As a user, I want a more obvious way to define the port of my application when import an application from Git.

Acceptance Criteria

1. Move the "Target port" option from the "Advanced Routing options" between the checkbox "Create a route to the Application" and "Show advanced Routing options" so that it is always visible (when the checkbox is marked)
2. Show the "Target port" option only when the "Create a route to the Application" checkbox is selected (similar to the current implementation)
3. Update the select component that the user does not need to click "Create <input>" after she/he entered a port. (Replace the Select prop isCreatable with isInputValuePersisted, see also https://www.patternfly.org/v4/components/select)

Additional Details:

None