Revert to previous multiapp state using previous commit and resolve old security issues

[tylers-username]

Our demo presents itself as a multiapp Upsun project example. This restores the app back to it's originally designed multiapp structure as it is currently a frontend app mocking multiapp functionality.

No changes were made to the code other than the revert. Security fixes applied in addition to reverting to previous commit.

[github-actions]

Hello, and thank you for contributing to the Upsun demo project!

Setting up tests

Until all tests pass, a pull request will not be merged.

Build tests for combinations of Python and Node.js will happen automatically, and must pass in order to merge.
Another test will actually runthrough all steps of the demo on a new project, but requires a repository admin to add the runthrough label to the pull request.

Failing tests

If your PR is failing, see the Running tests section of the README for troubleshooting details.

Reviewing these changes locally:

1. Clone this repo

   git clone -b revert/retore-multiapp-demo git@github.com:platformsh/demo-project.git demo-test-revert/retore-multiapp-demo && cd demo-test-revert/retore-multiapp-demo

2. Create a project on Upsun:

   upsun project:create --title "Demo Project test (pr-424/merge)" --default-branch revert/retore-multiapp-demo

   This command will set the local repository remote automatically, but you will need to specify the organization and region.

3. Push to Upsun:

   upsun push

[tylers-username]

Reviewed:

• Revert commit
• Dependency security warnings
• Upsun demo flow Upsun CLI command changes to ensure passing tests