[RFC] Feature/new backend breadcrumb trail

[agoat]

This is the PR to #602 to handle unlimited child tables in the breadcumb trail.

It goes recursively through all the parent tables and trys to add the table name and the objects title or name.
If a table name is shown or not can be controlled whether there is a translation or not.
I also added a suggestion to style the table and the object names differently for a better readability.

Additionally extra translation should be added in the contao/news-bundle to show the tables name (in modules.xlf):

      <trans-unit id="MOD.tl_news">
        <source>Articles</source>
      </trans-unit>

If someone want to see this in action, I can send the login data for my dev server via email.

[xchs]

Typo: breadcrumb

[leofeyer]

@contao/developers /cc

[Toflar]

Haven't tested it but looks neat! 👍 Thanks for contributing @agoat! I was just thinking about whether this needs to be modifiable/extensible somehow. But I haven't had the use case yet and we could still add an event later on if we want to.

[aschempp]

Thanks! A quick code review looks good to me 😎
There are a few indentation issues (especially in the XLIFF) but these are minor things, @leofeyer will fix the coding style anyway ^^

[agoat]

Just a quick example of how it look like:

And a very extreme one using circular parent tables (thats why I have made this PR):

[leofeyer]

Thank you @agoat. 👍