[JetBrains] Ensure prebuilt workspaces using Maven Wrapper are properly initialized in IntelliJ IDEA

[felladrin]

Description

Currently, repositories using Maven Wrapper may fail to be loaded as a Maven Project if they are prebuilt with some specific file combination and then opened in JetBrains IntelliJ IDEA in Gitpod.

In summary:

• When you use a prebuild of a repository containing a .xml file inside .idea folder, it won't load the Maven Projects correctly.
  You can see this behaviour by selecting Stable IntelliJ IDEA and starting a workspace from this URL.
• There's no problem if the repository has no .idea folder.
  You can see this behaviour by selecting Stable IntelliJ IDEA and starting a workspace from this URL.
• There's no problem if it has the files .idea/misc.xml, .idea/modules.xml, and .idea/spring-petclinic.iml.
  You can see this behaviour by selecting Stable IntelliJ IDEA and starting a workspace from this URL.
• There's no problem if the workspace hasn't been prebuilt.

This PR reinitializes the Maven Project Manager after the IDE is loaded, so it overcomes the issue of Maven Project not being detected when JetBrains Client connects.

References:

• IntelliJ Platform Plugin SDK > Optional Plugin Dependencies
• IntelliJ Platform Plugin SDK > Plugin Components > Project Open

Related Issue(s)

• Fixes [jb] mavenprojects are not imported automatically with warm-up in prebuilds #10185
• Fixes [jb] Ensure workspaces containing the Maven Wrapper start with it correctly configured #13100
• Epic: JetBrains Prebuilds for Maven #6740
• Gradle and Maven project configuration in JetBrains #10578
• YouTrack: ProjectService not being loaded inside an optional import

How to test

1. Open the preview environment of this PR: https://ak-init-maven.preview.gitpod-dev.com/
2. Select IntelliJ IDEA as your editor. It works for both Stable and EAP versions.
3. Access the following URL to start the prebuild of a workspace using Maven Wrapper and not containing .idea folder: https://ak-init-maven.preview.gitpod-dev.com/#prebuild/https://github.com/gitpod-io/spring-petclinic/tree/felladrin/prebuilt-maven-project-without-iml-file
4. Wait for the prebuild to finish and the workspace to start.
5. Confirm if the IDE opens and the Sync of Maven Modules start automatically:
   
6. Confirm if Run Configurations works appropriately by clicking the Play / Debug icons:

(Optional) Extra tests you can run on this Preview Environment

• Try a non-prebuilt workspace containing Maven Wrapper.
• Try another IDE (e.g. PyCharm) to confirm this addition isn't affecting the IDE to load.
• Try the empty repository.

Release Notes

[JetBrains] Fixed an issue preventing opening prebuilt Maven projects properly

Post-merge actions

• Delete files .idea/modules.xml and .idea/spring-petclinic.iml from https://github.com/Gitpod-Samples/spring-petclinic
• Delete branches felladrin/prebuilt-maven-project-without-idea-folder and felladrin/prebuilt-maven-project-without-iml-file from https://github.com/Gitpod-Samples/spring-petclinic

Werft options:

• /werft with-preview
• /werft with-large-vm

[akosyakov]

we tried together, and it seems to improve importing after prebuilds