Updated to Angular 11 and Nebular 7. Implemented Keycloak integration

angular.json

browserslistrc

e2e/tsconfig.base.json

package-lock.json

package.json

src/app/@core/core.module.ts

src/app/@theme/components/header/header.component.html

src/app/@theme/components/header/header.component.ts

src/app/@theme/styles/styles.scss

src/app/app-routing.module.ts

src/app/app.component.ts

src/app/app.module.ts

src/app/auth/callback/auth-callback.component.ts

src/app/auth/login/auth-login.component.ts

src/app/auth/logout/auth-logout.component.ts

src/app/auth/oauth/model/idmroles.spec.ts

src/app/auth/oauth/model/idmroles.ts

src/app/auth/oauth/model/idmuser.spec.ts

src/app/auth/oauth/model/idmuser.ts

src/app/auth/oidc/oidc.ts