Removed duplicate menu button in navbar header.

Created by: membrq

Checklist

• I have read the Contribution & Best practices Guide.
• My branch is up-to-date with the upstream master branch.
• The tests pass locally with my changes.
• I have added tests that prove my fix is effective or that my feature works(if appropriate).
• I have added necessary documentation (if appropriate).

Short description of what this resolves/which issues does this fix?:

• #1910 (closed) Extra menu button in navbar when browsing website on mobile (on user side)

Changes proposed in this pull request:

• Removed duplicate menu button.
• Added HTML style tag to float button to the right in the navbar header.