password strength display implemented

[arshiamoghimi]

It adds password strength display to entry details. Fixes #143

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✅ Hamedamz
❌ Arshia Moghimi

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[hpoul]

thanks for your contribution - #143 is actually about showing the password strength (and entropy) if the password generator, not in the entry details. but i'd be fine with this as well..
but then it should be coupled with the password field.. (there can be multiple) and there shouldn't be any static state/variables. I hope that makes sense.

[hpoul]

This looks wrong.. never use static variables for state. There has to be a better way for communicating with the child widget.

I also don't quite understand it, as there can be multiple passwords in one entry.. which one will this show the strength of? is not really obvious to me. I think this should all be encapsulated in the password field.