Modify 500 code error response page

[DenTray]

At the moment if package can't open a documentation (by any reasons) it will show the next page

To get information about the error - need to open a console and check there or go to logs.

Need to find a way to make this case more understandable and show error on the page.

Need to check all other documentation viewers, if it is a problem of the swagger viewer only - fix it, or implement more common solution.

[DenTray]

@RGO230 please check next case:

1. try to put incorrect json structire to the documentation file
2. try to open documentation

Now it works as earlier without error message displaying

Let's also modify the error view, as the current view is not enough targeting on the error

maybe there is a way to use the native error template from the first screen?