[enh] Enable compat with Android SDK 29 (use AndroidX instead of support-v4)

[fix] Remove unused files (bower files)

[fix] Fix avatar and pictures edition, on web extension artifact (avoid script inside HTML template, like "angular.element(this)" for security reason) - fix #904

[fix] Change bower versions, to use exact match (to avoid error in NPM log)
[enh] Upgrade undercore lib

[fix] Do not start currency service when waiting BMA (node can be changed by user)

[fix] Remove web site installation in README.md
[fix] Add web extension installation in README.md