### Description

Add support for Confluence Raw Blocks that let's CSF just "pass-through" to Confluence.

### Steps to Reproduce
- Create the following quarto document

````
---
title: "Simple Doc - Confluence Raw Block"
format: native
---

```{=confluence}
<ac:task-list>
    <ac:task>
        <ac:task-id>1</ac:task-id>
        <ac:task-status>incomplete</ac:task-status>
        <ac:task-body><span class="placeholder-inline-tasks">Al</span></ac:task-body>
    </ac:task>
    <ac:task>
        <ac:task-id>2</ac:task-id>
        <ac:task-status>incomplete</ac:task-status>
        <ac:task-body><span class="placeholder-inline-tasks">JJ</span></ac:task-body>
    </ac:task>
</ac:task-list>
```
````
- Publish to Confluence

### Expected Result
The task list (and other such Raw Blocks) are preserved.

### Actual Result
It is filtered out.

cwickham
2023-02-23T08:44:59Z
allenmanning
documentation enhancement publishing-confluence
v1.3
closed
Add Support: Confluence Raw Block
https://github.com/quarto-dev/quarto-cli/issues/4472