improve student review textarea and md-div style

[mpjk]

Short description

Updated styles in textarea to resizable and div height matching text height, to achieve better readability.

Note: Did not manage to set up test environment according to the documentation, so deployability is not ensured.

DoD

I have:

• added actual code.
• produced clean code that passes ESLint.
• code that actually does what it should.
• documented the code or added documentation to the wiki.
• added or modified test(s).
• test(s) that actually pass.
• works in trunk branch