So I added new project sources in an existing project in intellij. Later, I was unable to remove it from the project view and hence have to start a new project.
I wanted to remove the ../app/web from project view. I edited the .blazeproject file and it removed the contents of the ../app/web directory but the empty ../app/web directory was still visible in the project view.
Yopu can unlink the module from the project in "Project Structure" dialog:
See the related documentation page: https://www.jetbrains.com/help/idea/project-settings-and-structure.html