Add SSO buttons to login dialog

SSO login buttons are dynamically added based on the authentication
provider config received from backend API.
5 jobs for sso-login in 5 minutes and 15 seconds
latest
Status Job ID Name Coverage
  Codestyle
passed #169043
nodejs
tslint

00:01:38

 
  Test
passed #169044
nodejs
unit_tests

00:01:44

 
  Build
failed #169045
angular
ngbuild

00:01:52

 
  Review
skipped #169046
nginx
review
skipped #169047
nginx allowed to fail manual
stop_review
 
Name Stage Failure
failed
ngbuild Build
chunk {2} polyfills.a723c36635c3a098c2aa.js (polyfills) 130 bytes [initial] [rendered]
chunk {3} styles.9a5fc758bc1bdb098fcb.css (styles) 217 kB [initial] [rendered]
chunk {scripts} scripts.e611bf743f88e3c9ed67.js (scripts) 17.7 kB [entry] [rendered]

ERROR in : Can't resolve all parameters for LoginComponent in /builds/arsnova/arsnova-lite/src/app/components/shared/login/login.component.ts: ([object Object], [object Object], [object Object], [object Object], [object Object], [object Object], ?, [object Object]).
src/app/components/shared/login/login.component.ts(13,44): error TS2307: Cannot find module '../../../models/api-config'.
src/app/components/shared/login/login.component.ts(46,41): error TS2304: Cannot find name 'ApiConfigService'.

ERROR: Job failed: exit code 1