Unnecessary use of Flow

[TheLukaszNs]

In the Massa javascript source files, we are using @flow syntax to use Flow to check the static types, but we are not really using any of its possibilities (the only real use is in the SampleText.js file).
We either should use the Flow static type checking or (I don't recommend this way) delete the @flow comments.

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Flow is a really good static type checker, why don't we use it to avoid all the bugs that we can possibly make?

[JaDogg]

@TheLukaszNs would you like to send a pull request?

[TheLukaszNs]

@JaDogg Sure, I'll work on that

[JaDogg]

@TheLukaszNs Thanks. 👍