- 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).

#200

The package was not a proper ECMA Script package and therefore can not 
be tree shaken properly and would unnecessarily increase the package 
size.

- Simplified the code logic. Verification is done once in the beginning 
and not on every element.
- Now uses semver to verify and compare version strings

TipTap for the newest beta features and jasmine because of some 
dependency error npm was showing.

Remove useless plugin and add rule overrides for e2e test dir.

This is ised to flatten objects for the proerties panel.

- Check if button element is available in the toolbox
- Add the button to the canvas
- Change button label and check reflection on the canvas

This includes a fix in the dispacker, which no more tries (and fails) to 
replace variable names.

Remove warning for used-before-defined.

The other one used some deprecated functionality. Also we have more 
control over what is happening now.

Based on TipTap which in turn is based on ProseMirror. No further assets 
are needed.

                                                         [style.height.%]="100"

The old one has bugs, like not setting background color. It also relies 
on deprecated API features, which may stop working any time.
TinyMCE did not exhibit any bugs so far.

This is the basic installation. rework of the whole DialogService and 
it's editors follows.

This uses kolkov/angular-editor.