Move `web-app-importer` to the web-extensions repo

[kulmann]

Description

The web-app-importer app currently is part of the monorepo because we didn't have anything else properly set up at the time of app development. It is not a core functionality and as such doesn't belong in the web monorepo. We want to move the entire app to a different repo (either its own repo or into the web-extensions repo, preferably the latter if nothing speaks against it) and release it like all our other non-core apps, because it makes kubernetes deployments easier to have the app assets available as docker image and then use the app config via the ocis apps.yaml file.

User Stories

• As a devops person, I want to have the web-app-importer app assets available as docker image so that I can use the usual app config mechanism.

Value

Easy deployment.

Acceptance Criteria

• Move web-app-importer into the web-extensions repo
• Release it like all the other apps in that repo
• Make sure this works for the current master of ocis and web / the latest rolling release
• We currently don't want to publish the app in the app store. It seems to serve an edge case only.

Definition of ready

• [ ] Everybody needs to understand the value written in the user story
• [ ] Acceptance criteria have to be defined
• [ ] All dependencies of the user story need to be identified
• [ ] Feature should be seen from an end user perspective
• [ ] Story has to be estimated
• [ ] Story points need to be less than 20

Definition of done

• Functional requirements
  • [ ] Functionality described in the user story works
  • [ ] Acceptance criteria are fulfilled
• Quality
  • [ ] Code review happened
  • [ ] CI is green (that includes new and existing automated tests)
  • [ ] Critical code received unit tests by the developer
• Non-functional requirements
  • [ ] No sonar cloud issues