Can't compare two XWikiDocument with password property initialized with a clear password anymore

Closing this issue as won't fix was rediscussed in the chat (https://matrix.to/#/!zdPfnFC0pUfwN5kZ4LKP2dXZ2jC266yFWKNeqgmJd4E/$4eIQnJvA23Zl_d8s5xaP4GD-ItC-KW-5j_D-z7Zxth0?via=matrix.xwiki.com&via=matrix.org&via=helsinki-systems.de)
The conclusion is that this issue shouldn't be close as it raises important question about how to compare passwords, that must be discussed further first.

So there is a real regression related to the fact that passwords are contained in pages and so having the comparison returning false lead to merge conflicts when upgrading extensions that contains passwords.
In general I believe we shouldn't compare the password values at all when performing equality checks of pages: it's possible that now we migrated password to their own property class and we don't rely anymore to StringClass it's easier to filter them out.
However we also need to ensure that saving objects with a password without changing its value won't suddenly randomly override it, and in the contrary that it's still possible to change their value through object editor.

So we need to be careful where the equality works and where it doesn't and we probably need to review the APIs we're using to set password values.