WIP feat(ImportFile): Add an ImportFile Component

[glekner]

What:
fix #241
A very early implementation of the ImportFile component.
There is no official design, only a proposed one:

• patternfly-design issue
• proposed design

The component receives the following props:

• maxSize - Maximum size allowed of a single file in bytes
• maxAmount - Maximum amount of files allowed
• acceptedTypes - Supported file types, the types collection can be found here

Link to Storybook:
Storybook

I wrote the CSS myself, and since i'm not very experienced with the language, any recommendations are more than welcome

[coveralls]

Pull Request Test Coverage Report for Build 978

• 0 of 0 (NaN%) changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 71.391%

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Totals
Change from base Build 964:	0.0%
Covered Lines:	1244
Relevant Lines:	1574

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💛 - Coveralls