Allow exposing apps pushed by kyma CLI

[kwiatekus]

Description
Kyma cli should support a new boolean --expose flag that would create an api-rule CR for the pushed application.
The api rule should be of minimum setup (and though requiring minimum input data from the user), i.e

• it should allow for public access for all paths and all HTTP methods
• it should assume the host name = app name
• it should use the default kyma gateway

So that :
kyma alpha app push --name mynginx --image nginx:latest --containerPort xx --expose true
would expose the mynginx deployment as https://mynginx.{cluster domain}/**

Reasons

It is an essential feature to allow developer to deploy the currently developed code to k8s runtime and to test it by calling it from outside the cluster

Related
Part of #2236
Depends on #2239