Link field: add the ability to have a static anchor text and link title

Using the link field from the contrib module, you can add a static "anchor text" and "link title", so that the user that fills in the field must enter only the URL. In my websites, I use very very much this feature. Unfortunately, it went lost moving link to core.

And, of course, it would be nice if these static texts could have support for tokens...

Example use-cases:

• A website that needs to store the link of an IOS or Mac OSX application in the App Store would need this feature to assign the "See [appname] in the App Store" (where [appname] is a token) to the anchor text of a link field without having the risk of publishers changing the exposed default value;
• You might want to set the anchor text of a link to the value of another field of your content type, but for some reason you need the value either as a field value and the anchor text;

In these two use-cases, you would need a static "link title" too if you want to enhance these links' accessibility.