[password/step3] Add feature 'show password'

[misstick]

Feature

• [x] Add feature (a toggle button: show/hide),
• [x] Add styles

[misstick]

Note : wait for https://github.com/cozy/cozy-proxy/pull/310/ merge this PR do not work anymore and I don't find why.

[misstick]

@gregorylegarec : I have changed from your review of last Thursday; is it OK for you?

[misstick]

@m4dz : I'm not sure about my SVG use; can you tell me if its OK?

[m4dz]

Ok for me for the SVG use, thanks!

I've got a little doubt about the from wrapping, but nevermind, we'll see that later if it really care :).

[gregorylegarec]

Thanks @misstick 👍