Stringification of big ranges

I happen to have a `CHECK(buffer1 == expectedbuffer)`, with each buffers being whopping a 5MB.

When you use the `-s` switch, catch2 is happy to print all of it, really really slowly.

**Expected behavior**
I would have expect the stringification of ranges to have some kind of limit. Both for performance and readability reason.

**workaround**

* Specialize StringMaker to do it, but this cumbersome, particularly with ODR.

* Use a hashed value of the buffer in the `CHECK` expression. Not pratical when you have lots of them.