Eureka (solved): ExpressionChangedAfterItHasBeenCheckedError (setTimeout) #88; sys-check adapted to app-root-approach

HttpclientModule removed from all submodules to enable http interceptor; superadmin status change UI added

iqb-berlin/testcenter-iqb-ng#89
iqb-berlin/testcenter-iqb-ng#82
iqb-berlin/testcenter-iqb-ng#84

first successful run after merging tc + admin; workspace monitor extracted from admin; testcontroller works; syscheck does not work; admin login failed

# Conflicts: (some are resolved directly, most are split into TC and ADMIN version)
#	.gitignore
#	README.md
#	angular.json
#	e2e/src/app.e2e-spec.ts
#	package-lock.json
#	package.json
#	src/app/about/about.component.html
#	src/app/about/about.component.ts
#	src/app/app-routing.module.ts
#	src/app/app.component.scss
#	src/app/app.component.spec.ts
#	src/app/app.component.ts
#	src/app/app.interceptor.ts
#	src/app/app.interfaces.ts
#	src/app/app.module.ts
#	src/app/backend.service.ts
#	src/app/maindata.service.spec.ts
#	src/app/maindata.service.ts
#	src/app/start/start.component.css
#	src/app/start/start.component.html
#	src/app/start/start.component.spec.ts
#	src/app/start/start.component.ts
#	src/app/superadmin/superadmin-routing.module.ts
#	src/app/superadmin/superadmin.component.css
#	src/app/superadmin/superadmin.component.html
#	src/app/superadmin/superadmin.component.ts
#	src/app/superadmin/superadmin.module.ts
#	src/environments/environment.build.ts
#	src/environments/environment.prod.ts
#	src/environments/environment.ts
#	src/index.html
#	src/polyfills.ts
#	src/styles.css
#	src/tsconfig.app.json
#	src/tsconfig.spec.json
#	src/tslint.json
#	tsconfig.json
#	tslint.json

implement endpoint `[GET] /system/config` replacing `[GET] /sysconfig` and preparation for https://github.com/iqb-berlin/testcenter-iqb-ng/issues/53

provide bookletDbId (testId) when calling [PUT] `test/${testId}/log` correctly even for BOOKLETLOADSTART
* it was not set in test-controller.service's this.bookletDbId, until bs.getBookletData is resolved (after reload for example)
* but call on [PUT] `test/${testId}/log` with BOOKLETLOADSTART was fired before
* in the old implementation bookletDbId was stored also (!) in the loginToken, so even if it was in fact provided via body of the call, tha backend knew the bookletDbId from the token and got it (only) from there.

Prepare admin

Edge fix