Add input/output labels and bottom result warning

[julien-nc]

Not sure about the labels, for the input, would something like "Text" be better?

[julien-nc]

How about "Text to summarize" und "Summary"? :)

Not possible now as we can't make sure the provider name is a verb or an action. We could do something like that once the TextProcessing API has been improved and forces the providers to define those labels.

Any idea of good generic labels?

[julien-nc]

@nimishavijay Much better with the warning block.

[julien-nc]

@jancborchardt Sure