[Feature Request]: Conditionally rendered component

### Prerequisites

- [x] I have searched existing issues to ensure this feature hasn't already been requested
- [x] I have tested using the latest version of docs-builder

### What problem are you trying to solve?

Release notes often need to be only published on a specific date.

The current method is to only merge the PR that contains the release notes.

However, there is no official process and people make mistakes. Which means sometimes PRs get merged to soon.

### Proposed Solution

Create a component that only renders based on a conditional. E.g. date.

```markdown

:::{conditional} $current_date >= 2025-06-03

## Some content

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Pellentesque mollis nunc eget tellus aliquam, ac dignissim mi dignissim. Etiam eget nulla ipsum. Nam tincidunt cursus velit sit amet dapibus. In laoreet lorem ac metus posuere, ut dignissim orci semper. Maecenas vitae pretium sem. Cras commodo nec erat ut lobortis.
:::

```

### Examples and Research

_No response_

### Alternative Solutions

_No response_

### Additional Context

_No response_

### How important is this feature to you?

Nice to have