Extension support

[r58Playz]

• Finish extension UI
• Background script logic
• Basic permissionless extension APIs
• Error handling on extension installation and injection
• Implement activeTab permission
• Implement alarms permission
• Implement background permission
• Implement bookmarks permission
• Implement browsingData permission
• Implement certificateProvider permission
• Implement clipboardRead permission
• Implement clipboardWrite permission
• Implement contentSettings permission
• Implement contextMenus permission
• Implement cookies permission
• Implement debugger permission
• Implement declarativeContent permission
• Implement declarativeNetRequest permission
• Implement declarativeNetRequestWithHostAccess permission
• Implement declarativeNetRequestFeedback permission
• Implement desktopCapture permission
• Implement documentScan permission
• Implement downloads permission
• Implement downloads.open permission
• Implement downloads.ui permission
• Implement enterprise.deviceAttributes permission
• Implement enterprise.hardwarePlatform permission
• Implement enterprise.networkingAttributes permission
• Implement enterprise.platformKeys permission
• Implement experimental permission
• Implement fileBrowserHandler permission
• Implement fileSystemProvider permission
• Implement fontSettings permission
• Implement gcm permission
• Implement geolocation permission
• Implement history permission
• Implement identity permission
• Implement idle permission
• Implement loginState permission
• Implement management permission
• Implement nativeMessaging permission
• Implement notifications permission
• Implement offscreen permission
• Implement pageCapture permission
• Implement platformKeys permission
• Implement power permission
• Implement printerProvider permission
• Implement printing permission
• Implement printingMetrics permission
• Implement privacy permission
• Implement processes permission
• Implement proxy permission
• Implement scripting permission
• Implement search permission
• Implement sessions permission
• Implement sidePanel permission
• Implement storage permission
• Implement system.cpu permission
• Implement system.display permission
• Implement system.memory permission
• Implement system.storage permission
• Implement tabCapture permission
• Implement tabGroups permission
• Implement tabs permission
• Implement topSites permission
• Implement tts permission
• Implement ttsEngine permission
• Implement unlimitedStorage permission
• Implement vpnProvider permission
• Implement wallpaper permission
• Implement webAuthenticationProxy permission
• Implement webNavigation permission
• Implement webRequest permission
• Implement webRequestBlocking permission