How to create a custom Allure step function for sensible data

#### I'm submitting a ...
- [ ] bug report
- [x] feature request
- [ ] support request => Please do not submit support request here, see note at the top of this template.

#### What is the current behavior?
With a step decorator like this:

Which takes an element (a text box) and enters the value in it. In the step function I display the value that I want to enter No matter what I enter on the step title, the report always shows the info that was passed as arguments to the function.

My report looks like the following image:

#### If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem
Not a bug

#### What is the expected behavior?
Thus, the "value" argument will always be displayed and that is something that I cannot have on certain projects. I could either use with not showing the value at all or to change it to something like '*****'. Is there anyway to make a custom step function that solves my problem?.

#### What is the motivation / use case for changing the behavior?
I am currently working on a Testing Automation team, using Python and Allure to make reports of all the test cases that we run. Sometimes we deal with sensible data (e.g: passwords) that I can't show directly on the reports due to data protection policies.

#### Please tell us about your environment:

- Allure version: 2.13.0
- Test framework: pytest@3.6.1
- Allure adaptor: pytest-allure-adaptor@1.7.10

#### Other information

[//]: # (
. e.g. detailed explanation, stacktraces, related issues, suggestions
. how to fix, links for us to have more context, eg. Stackoverflow, Gitter etc
)

Beginne damit, den Step-Dekorator und den Weg von seinen Argumenten bis zum Titel des Allure-Berichts zu überprüfen. Prüfe das im Issue beschriebene Verhalten des pytest-Adapters und ermittle, wie ein benutzerdefinierter Step sensible Werte wie Passwörter weglassen oder maskieren könnte. Erledigt ist die Aufgabe, wenn ein benutzerdefinierter Step einen nützlichen Bericht erzeugen kann, ohne sein sensibles Argument offenzulegen.

Vom Indexierungsmodell aus dem Issue-Text verfasst.