Add ability to run against local containerized backend

[matthijsgroen]

What

Adds ability to tie the frontend to a local running backend instead of the staging environment

Why

There was no option to run the frontend against a local backend

Code Review

Please consider the following checklist when reviewing this Pull Request.
More background and details here.

• Does the code actually solve the problem it was meant to solve?
• Is the code covered by unit tests? Integration tests?
• Does anything here need documentation? (Focus on why, not what.)
• Does any of this code deal with privacy sensitive information or affects security? Ask an additional reviewer.
• Is the code easy to understand and change in the future?
• Is the same code or concept duplicated? Find a balance between DRYness and readability.
• Does the code reasonably adhere to the Kabisa coding standards?
• Be kind.

[codeclimate]

Code Climate has analyzed commit dd33d3d and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (50% is the threshold).

This pull request will bring the total coverage in the repository to 71.5% (0.0% change).

View more on Code Climate.