Remove the form-control-wrapper from several form docs

[oliverschuerch]

The wrapper class was not implemented as specified (around the label, input and hint-text element) and should be removed for the following components:

• input
• select
• textarea
• slider

[oliverschuerch]

@rouvenpost I changed the behaviour of the above mentioned form-control elements when validated and focused.
Please have a look at the following pages:

• input
• select
• textarea
• slider

Set the Validation property to Valid or Invalid and focus the control afterwards to see, what I've done ;)