Combine authentication settings section from the integration configuration with configuration edit in new integration settings page

For API as Product we need to extract the authentication settings section from the Proxy configuration/integration page to its proper page. We will use the new configuration settings page and combine authentication settings with the current integration settings page as the authentication form changes depending on the authentication method chosen:

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• We'll get rid of the current graphical form and turn it into a normal one.
• Idea is that auth part of the form will update itself based on which one you choose at the top:
• we no longer support plugins: confirmed: https://issues.jboss.org/browse/THREESCALE-2395 we do support rest but there is no ui needed for that, so options should be: apicast (2x) & istio.
• we also put response codes in the new settings page too.
• before releasing apiap on saas we need to check as current customers using them should continue to be served and we might consider https://issues.jboss.org/browse/THREESCALE-2395?focusedCommentId=13786268&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13786268