- A suitable version was not available after update of Angular
- Reactivate test for valid pages

with ng update @angular/material@16 @angular/cdk@16
- run npm audit fix

- run npm audit fix to fix some critical vulnerables

Uses external software 'MathLive'.

Distpacker issues with mathlive have been solved in a custom 
distpacker.ts in scripts-folder. This is now used instead of the 
distpacker from the npm package.

#298

This reverts commit da09ac1e.

This way elements can handle their logic themselves without having to
rely on outside utility classes.

Also restructure files in common in a more logical way.

- upgrade @ngx-translate/core
- upgrade rxjs
- upgrade testcafe

- run npm update

The package karma-spec-reporter is to show more info about run tests on 
the console.

Numbers on the test files refers to the version (2 digits for minor; 
patch number ignored).