New design

[TomaszGasior]

• Get rid of tabbed UI.
• Change form items layout from horizontal to vertical (label above field).
• Use new version of the logo.
• Use form item 'help' property instead of information paragraph.
• Simplify radio table create form.
• Show form's validation errors inline instead of notification. Simplify maintenance of validation error messages by using defaults from Symfony.
• Split radio table remove form and radio station remove form.
• Split export section from radio table settings.
• Split columns section from radio table settings.
• Make top site header smaller, make it sticky. Make logo smaller and merge two lines of navigation into one.
• Change background color, buttons colors, input colors. Use gray instead of green and orange, except for accents. Make it more elegant.
• Replace fake checkboxes with real checkboxes.
• Style color & unit input fields as 100% width. Use integrated with input style for unit input fields.
• Make site width a little bit bigger.
• Desktop variant since 768 px.
• Place some form fields side-by-side when applicable.
• Add remove functionality to radio station edit form.
• Use sticky-to-bottom placement for "save changes" button in radio station edit form.
• Introduce left-right columns UI.
• Make footer bigger and more readable.
• Add skip links for keyboard-driven users.
• Make description about public profile more clear, add profile link in account settings.
• Get rid of remove radio table page, merge it with radio table settings.
• Redesign homepage: new layout, bigger logo on navigation bar.

[TomaszGasior]

This issue has been replaced by https://github.com/TomaszGasior/RadioLista-v3/milestone/1 milestone and separate issues:
#198
#181
#182
#183
#184
#185
#186
#187
#188
#189
#190
#191
#192
#193
#194
#195
#196
#197