Created a File Class

[jimmywarting]

I got two packages that would very much need a File class, I know @octet-stream could need one as well. I added it as a separate file (file.js) that also extends the Blob class.
Therefore i have also added the fileFrom and fileFromAsync methods to from.js as well

I also added the option to pass in a mimetype in in all 4 methods so it can set the type on the blob/file so it dosen't have to be wrapped again in a new blob or file

closes #91

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I also took the opportunity to extract the DOMException from NodeJS itself and removed the dependency on DOMException package

closes #96

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Also updated all dependencies and fixed the new lint rules by xo

closes #95

[codecov]

Codecov Report

Merging #97 (b5fa0bd) into master (8ef89ad) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #97   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            2         3    +1     
  Lines          289       350   +61     
  Branches        44        51    +7     
=========================================
+ Hits           289       350   +61     

Impacted Files	Coverage Δ
file.js	100.00% <100.00%> (ø)
from.js	100.00% <100.00%> (ø)
index.js	100.00% <100.00%> (ø)

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[octet-stream]

LGTM