use ng2-pdf-viewer + fix some viewer pdf error + add prod mode build

package.json

src/frontend/app/document/document.component.html

src/frontend/app/document/document.component.ts

src/frontend/app/login/login.component.html

src/frontend/app/login/login.component.ts

src/frontend/app/service/notification.service.ts

src/frontend/app/service/signatures.service.ts

src/frontend/app/signatures/signatures.component.html

src/frontend/app/signatures/signatures.component.ts

src/frontend/core/environments/environment.prod.ts

src/frontend/core/environments/environment.ts

src/frontend/core/index.html

src/frontend/core/tsconfig.app.json