Bug 993318 - [Settings] build script improvement for load time

- prompt to alameda 0.2
Bug 994702 - making an incorrectly visible callscreen 'hold' text an aria label. r=Rik
Merge pull request #18157 from gasolin/issue-993318

Bug 993318 - [Settings] build script improvement for load time, r=arthur
Merge pull request #18335 from yzen/bug-994702

Bug 994702 - making an incorectly visible callscreen 'hold' text an aria...
Bug 968661 - Extract new build module webapp-shared.js from webapp-zip.js