Alias Handler for SCIM Users

[adrianhoelzl-sap]

see issue #2505

Preparation for alias feature for SCIM users; adds subclass of EntityAliasHandler that handles alias entities of SCIM users.

Prerequisites:

• #2765
• #2824

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/187191383

The labels on this github issue will be updated when the story is started.

[peterhaochen47]

Hi, as this PR is a stepping stone toward the overall "alias feature," and as it looks like the changes are limited to the specific code paths related to the feature, I would defer the approval of this PR to @strehle, in terms of judging 1) whether this PR accomplishes its goal, and 2) wether this PR has enough test coverage and user docs (if applicable).

I'll also approve as well as long as our prior understanding the "alias feature" are still true after this PR: That the functionality & performance of all the existing UAA features are not impacted (do not experience breaking changes / regressions) when the "alias feature" is not turned on (and the feature is off by default).

[strehle]

@adrianhoelzl-sap please cleanup PR , see https://sonarcloud.io/project/issues?resolved=false&sinceLeakPeriod=true&pullRequest=2769&id=cloudfoundry-identity-parent

Rest is ok

[Tallicia]

@adrianhoelzl-sap please cleanup PR , see https://sonarcloud.io/project/issues?resolved=false&sinceLeakPeriod=true&pullRequest=2769&id=cloudfoundry-identity-parent

Rest is ok

@strehle This link is not showing no results for me:

[strehle]

@adrianhoelzl-sap please cleanup PR , see https://sonarcloud.io/project/issues?resolved=false&sinceLeakPeriod=true&pullRequest=2769&id=cloudfoundry-identity-parent Rest is ok

@strehle This link is not showing no results for me:

there where updates and now smells are solved See overview https://sonarcloud.io/summary/new_code?id=cloudfoundry-identity-parent&pullRequest=2769

[strehle]

@Tallicia do you have open issues here ?

[torsten-sap]

I merge this PR as all questions seem to be addressed and two approvals exist.