Removed all references to DLL

[realmayus]

Closes https://github.com/corona-school/project-user/issues/427

[lsc0498]

@realmayus Can you check for this building issue? This is the corresponding log from Heroku:

-----> Building on the Heroku-18 stack
-----> Using buildpack: mars/create-react-app
-----> React.js (create-react-app) multi app detected
=====> Downloading Buildpack: https://github.com/heroku/heroku-buildpack-multi.git
=====> Detected Framework: Multipack
=====> Downloading Buildpack: https://github.com/heroku/heroku-buildpack-nodejs.git
=====> Detected Framework: Node.js
       
-----> Creating runtime environment
       
       NPM_CONFIG_LOGLEVEL=error
       USE_YARN_CACHE=true
       NODE_ENV=production
       NODE_MODULES_CACHE=true
       NODE_VERBOSE=false
       
-----> Installing binaries
       engines.node (package.json):  unspecified
       engines.npm (package.json):   unspecified (use default)
       engines.yarn (package.json):  unspecified (use default)
       
       Resolving node version 16.x...
       Downloading and installing node 16.13.2...
       Using default npm version: 8.1.2
       Resolving yarn version 1.22.x...
       Downloading and installing yarn (1.22.17)
       Installed yarn 1.22.17
       
-----> Installing dependencies
       Installing node modules (yarn.lock)
       yarn install v1.22.17
       [1/4] Resolving packages...
       error Your lockfile needs to be updated, but yarn was run with `--frozen-lockfile`.
       info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
-----> Build failed
 !     Outdated Yarn lockfile
       Your application contains a Yarn lockfile (yarn.lock) which does not
       match the dependencies in package.json. This can happen if you use npm
       to install or update a dependency instead of Yarn.
       Please run the following command in your application directory and check
       in the new yarn.lock file:
       $ yarn install
       $ git add yarn.lock
       $ git commit -m "Updated Yarn lockfile"
       $ git push heroku main
    
       https://help.heroku.com/TXYS53YJ
 !     Push rejected, failed to compile React.js (create-react-app) multi app.
 !     Push failed

It's probably simply merging master into the branch and then executing yarn install.