fixes #5623

issue #5082

API is not finished.

issue #5082

this commit breaks the apidoc extension. will adjust it afterwards.

fixes #5147

fixes #5104, fixes #5101

New syntax:

```
[link to guide](guide:file-name.md)
[link to guide](guide:file-name.md#subsection)
```

fixes #4719

Improved checks where substr_compare is used, replaced more substr + comapre cases with substr_compare

issue #746

Fixes #3358: Removed automatic CSRF meta tag generation by `View`. Added `Html::csrfMetaTags()` and its call to main layout files

added class references (current version without hyperlink)

- better title page,
- book style,
- improved internal linking using labels and references