Rename "password" to "passphrase" and explain better what it is about

[BTCparadigm]

Discussed in #5258

^{Originally posted by ibertario February 24, 2021}
As commented before:

The password (passphrase is better IMO) is used as a 13th word so the textbox to enter the password should be after the recovery words specially when generating a wallet.
The password textbox below the wallet name looks like it is used just to load the wallet and I think this is why users get confused and do not backup their password.

Originally posted by @yahiheb in #4005 (comment)

I don't agree with calling it password as well because it is also a passphrase which is required to recover your funds, so writing down anything related to your wallet recovery isn't a bad practice IMO and of course store them separately from the recovery words.

Originally posted by @yahiheb in #4263 (comment)

And...

Passphrase, as described in BIP39:
https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki#from-mnemonic-to-seed

A user may decide to protect their mnemonic with a passphrase. If a passphrase is not present, an empty string "" is used instead.
...
because every passphrase generates a valid seed (and thus a deterministic wallet) but only the correct one will make the desired wallet available.

Terminology and description

Operationally, the passphrase is part of the seed, because if it changes it generates a different seed. This is not the behavior of a "password".

It can be described as the 13/19/25th "part" of the seed (bacause it can be anything and not just a word).

The good naming and description can prevent the user from only saving the 12/18/24 words, believing that the password is to unlock the wallet in Wasabi, for example.

Memorizing, writing or making any backup of the passphrase

IMO is better explain the options and security measures that the user has, the dangers associated with each option, and let then the user decide.

Don't indicate what to do.

Not all users have the same memory, save for the same amount of time, nor do they need the same security or operation.