Make markdown components for reports and pages full width

[hexylena]

This pull requests makes all components full width in the report interface. It fixes #11564 and the issues with content flowing weirdly because all of the boxes were float: left.

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. Make a workflow
  2. add a report
  3. run the workflow
  4. see that the report has full-width components

License

• I agree to license these contributions under Galaxy's current license.
• I agree to allow the Galaxy committers to license these and all my past contributions to the core galaxy codebase under the MIT license. If this condition is an issue, uncheck and just let us know why with an e-mail to galaxy-committers@lists.galaxyproject.org.

[mvdbeek]

Should we highlight this @hexylena ? @pcm32's report in #12455 (comment) should look really good now :)

[hexylena]

Yeah why not, it's a user facing thing that makes their life better. Good suggestion! :)