Migrate from apollo-server-express to apollo-server

[KristianWEB]

Is your feature request related to a problem? Please describe.
We need to migrate to apollo-server because we are having problems with suscriptions implementation.

You can work on this feature by creating and using a branch called feature/apollo-server-migration

Pull Request Squashing

Please, go through these steps before you submit a PR.

1. Make sure that your PR is not a duplicate.
2. If not, then make sure that:

2.1. You have done your changes in a separate branch. Branches MUST have descriptive names that start with either the fix/ or feature/ prefixes. Good examples are: fix/signin-issue or feature/issue-templates.

2.2. You have a descriptive commit message with a short title (first line).

2.3. You have only one commit (if not, squash them into one commit).

2.4. npm test doesn't throw any error. If it does, fix them first and amend your commit (git commit --amend).

3. After these steps, you're ready to open a pull request.

3.1. Give a descriptive title to your PR.

3.2. Provide a description of your changes.

3.3. Put closes #XXXX in your comment to auto-close the issue that your PR fixes (if such).