Kickoff redesign

This commit completely overhauls Kickoff's user interface!

Original design (UI/UX) discussion

• https://phabricator.kde.org/T12192
• !186 (closed)

Features / issues

New:

• Double pane UI
• Both keyboard and mouse navigation have been overhauled
• Power/Session actions are available in the footer
• Improved RTL support
• Grid view
• All applications view
• Accessibility

Screenshots / Videos

Apps

Places

Search

Accessibility

https://youtu.be/Vqah3yL5h_E

Bugs fixed

BUG: 357379

BUG: 369159

BUG: 369405

BUG: 378815

BUG: 387510

BUG: 387797

BUG: 391383

BUG: 392005

BUG: 393401

BUG: 394924

BUG: 398234

BUG: 398279

BUG: 398349

BUG: 398350

BUG: 398352

BUG: 398353

BUG: 405674

BUG: 408313

BUG: 410018

BUG: 412090

BUG: 415392

BUG: 416423

BUG: 419169

BUG: 423160

BUG: 425970

BUG: 426329

BUG: 427846

BUG: 428297

FIXED-IN: 5.21

@teams/vdg