Media queries for elements inside #urlInput need improving

[luixxiul]

Describe the issue you encountered:

Expected behavior: Media queries for elements inside #urlInput need improving. It seems to me that we do not need max-width here at all. Here is my suggestion:

• Set width: 135px to .WindowCaptionButtons, which seems to be static (correct if I'm wrong)
• Set width: calc(100% - 135px) to .navbarMenubarFlexContainer
• Remove max-width properties based on platforms from #urlInput

By doing these we should get this:

• Platform (Win7, 8, 10? macOS? Linux distro?): Windows 10 JP
• Brave Version: 0.12.2 RC1
• Any related issues: Titlebar on Windows has a lot of wasted space #3036

[jonathansampson]

All that is really needed is to set the input element's width to 100%.

I have this change in a commit, and will issue a PR.