Feature Request: Provide `transparent` option value to templates in the `section` object

[ararunaufc]

Bug Report

Environment

Zola version: 0.15.3

Expected Behavior

I described the problem I had in more detail here.

In a nutshell, I'd like to have access to the value provided to the transparent option of a section when in a template.

Current Behavior

As a workaround, I'm duplicating the option in the [extra].

Step to reproduce

(Not applicable)