website/docs: Password Uniqueness Policy (#13686)

* First draft docs for policies/unique_password

* simplify documentation

* fix styling

* Add clarification about when this policy takes effect

* change wording in how it works

Co-authored-by: Dominic R <dominic@sdko.org>
Signed-off-by: Marcelo Elizeche Landó <marce@melizeche.com>

* Take the user by the hand and tell them where to go

* Improve wording in Configuration options

* add suggestion from PR

Co-authored-by: Dominic R <dominic@sdko.org>
Signed-off-by: Marcelo Elizeche Landó <marce@melizeche.com>

* Update website/docs/customize/policies/unique_password.md

Signed-off-by: Tana M Berry <tanamarieberry@yahoo.com>

* Apply suggestions from code review

Co-authored-by: Tana M Berry <tanamarieberry@yahoo.com>
Signed-off-by: Marcelo Elizeche Landó <marce@melizeche.com>

* fix linting and wording

* Add instructions for binding

* Remove conf options section, add to sidebar

* Update website/docs/customize/policies/unique_password.md

Signed-off-by: Tana M Berry <tanamarieberry@yahoo.com>

---------

Signed-off-by: Marcelo Elizeche Landó <marce@melizeche.com>
Signed-off-by: Tana M Berry <tanamarieberry@yahoo.com>
Co-authored-by: Dominic R <dominic@sdko.org>
Co-authored-by: Tana M Berry <tanamarieberry@yahoo.com>

website/sidebars.js

@@ -396,6 +396,7 @@ export default {
                                 "customize/policies/expression/managing_flow_context_keys",
                             ],
                         },
+                        "customize/policies/unique_password",
                     ],
                 },
                 {