Add user details as a context "variable" available to markdown

[philippkahr]

Describe the feature:

When creating markdown in a dashboard it would be cool to create something like:

Hello {{ user.first_name }}

You are viewing the dashboard xyz

{{ user.name }}  => philippkahr {{ user.friendly_name }} => Philipp Kahr {{ user.first_name }} => Philipp ....

Describe a specific use case for the feature:

Personified greetings in markdown

E.g.

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[elasticmachine]

Pinging @elastic/kibana-visualizations @elastic/kibana-visualizations-external (Team:Visualizations)

[stratoula]

I am adding both teams hare as:

• the presentation team owns the static markdown in the dashboard
• the visualizations team wants to add markdown in Lens so this could be a potential feature

[ThomThomson]

I'm going to remove the Presentation team from this issue as I'd argue that these kinds of context variables would be better suited for the heavier Lens version of markdown.

[stratoula]

@ThomThomson I don't think we have concluded that the new markdown is going to be a Lens chart. There are conversations about being a dashboard flyout if I am not wrong. Just fyi

[ThomThomson]

Ah - I thought that the Lens Markdown was already planned, and the Dashboard inline markdown was envisioned to be something smaller. I think we'll need some input on product from this. @teresaalvarezsoler what is the latest communication regarding the new markdown?

[teresaalvarezsoler]

We are still in discussions but the vision is to have only one markdown panel and it will likely be part of dashboards since it does not make sense to have markdown panels as a stand alone viz outside dashboards.

[philippkahr]

It could make sense for canvas as well.