Implement Maven-friendly way to use UI build files in API jar

[JohnKallies]

As an OSMT developer, I want to have want a simple typical Angular development workflow with the Angular build files available in the Spring app jar file.

Currently, ui/angular.json uses this to put the Angular files in the API module, in a directory that is ignored by git.

• "outputPath": "../api/src/main/resources/ui/",

Maven has a more idiomatic way to do this, using the Maven Assembly plugin

• https://maven.apache.org/plugins/maven-assembly-plugin/

This card proposes:

• In the UI Module:

  • Building the Angular files in the expected ui/dist folder
  • Building a jar for the UI module using mvn install
    • The approach within the UI module is similar to this article (below), except they are building a war. Our intention here is to include the output of ui/dist as a resource for the API module, so a jar artifact is more appropriate.
    • https://vorozco.com/blog/2019/2019-09-11-Packagin-Angular-8-Apps-War.html

• In the API module:

  • We should expect to declare a dependency on the UI module jar
  • Maven Assembly should be configured to unpack that jar in the API module's resources directory

When complete, ng serve should still proxy front end requests on port 4200, from the ui/dist folder.

This will also simplify future work related to whitelabelling, allowing the UI code and npm tasks to cleanly live within the boundaries of the UI module.