Rewrite ControlledModal

[mpotomin]

Rewrite current ControlledModal in order to:

1. Stop requiring component consumers to use <ControlledModalContent> from the neighbour Confirm.tsx component, since ControlledModal already wraps its children into the Content container
2. Stop requiring component consumers to use <Actions> from the neighbour Confirm.tsx component, since actions can be passed as a prop to the ControlledModal component

Issues to consider:

1. Possibility to embed a <Form> element into the Modal
2. Prevent re-rendering of the whole page each time anything in the modal changes.