Add float comparison tolerance parameters to freetext directive

[ihalaij1]

Description

What?

Add float comparison tolerance parameters to the freetext directive, because MOOC-Grader now supports configurable relative and absolute tolerances instead of the previously hardcoded 2% relative tolerance.

Fixes #158

Testing

What type of test did you run?

• Accessibility test using the WAVE extension.
• Django unit tests.
• Selenium tests.
• Other test. (Add a description below)
• Manual testing.

Tested that these changes work with the new changes in MOOC-Grader

Did you test the changes in

• Chrome
• Firefox
• This pull request cannot be tested in the browser.

Translation

• Did you modify or add new strings in the user interface? (Read about how to create translation)

Programming style

• Did you follow our style guides?
• Did you use Python type hinting in all functions that you added or edited? (type hints for function parameters and return values)

Have you updated the README or other relevant documentation?

• documents inside the doc directory.
• README.md.
• Aplus Manual.
• Other documentation (mention below which documentation).

Is it Done?

• Reviewer has finished the code review
• After the review, the developer has made changes accordingly
• Customer/Teacher has accepted the implementation of the feature

[PasiSa]

Looks good to me (although I haven't played with rst-tools much). In my opinion we could merge this at the same time with the related grader PR.

[markkuriekkinen]

Good!