Upgrade Angular to 7+ version.

[heloufir]

Main changes:

• Upgrade Angular dependencies from ^6.1.0 to ^7.2.6
• Upgrade ng-bootstrap from ^3.3.0 to ^4.0.4
• Upgrade bootstrap from ^4.1.3 to >=4.3.1
• Upgrade core-jg from ^2.5.4 to ^2.6.5
• Add hammerjs ^2.0.8 dependency
• Upgrade rxjs from ~6.2.0 to ~6.4.0
• Upgrade rxjs-compat from ^6.3.3 to ^6.4.0
• Upgrade zone.js from ~0.8.26 to ~0.8.29
• Remove @angular/cli
• Upgrade @angular/compiler-cli and @angular/language-service from ^6.1.0 to ^7.2.6
• Upgrade typescript from ~2.9.2 to ~3.1.1