Registration/Login HTML form: remove request field and ensure method is set

[zepatrik]

Related issue

closes #178

Proposed changes

The request field will not be added any more. The tests make sure it is not present.
We also check from now on that the form method is always set.

Checklist

• I have read the contributing guidelines
• I have read the security policy
• I confirm that this pull request does not address a security vulnerability. If this pull request addresses a security
  vulnerability, I confirm that I got green light (please contact security@ory.sh) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation within the code base (if appropriate)
• I have documented my changes in the developer guide (if appropriate)

Further comments

[aeneasr]

Very nice!