text: Title: Support admonitions / alerts / callouts in markdown
  Body: ### Checklist
  
  - [x] I have searched the [existing issues](https://github.com/streamlit/streamlit/issues) for similar feature requests.
  - [x] I added a descriptive title and summary to this issue.
  
  ### Summary
  
  Implement support for alert blocks (aka admonitions) within the Streamlit markdown flavour. 
  
  ### Why?
  
  This is supported by many other markdown flavours as well.
  
  ### How?
  
  Unfortunately, there isn't one common syntax for this... we probably have to choose between one of these:
  
  [Github markdown](https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax):
  
  > [!NOTE]  
  > This is a note alert block
  
  ```
  > [!NOTE]  
  > This is a note alert block
  ```
  
  [PyMdown](https://facelessuser.github.io/pymdown-extensions/extensions/details/):
  
  ```
  ??? note
     This is a note alert block
  ```
  
  [Material for Mkdocs](https://squidfunk.github.io/mkdocs-material/reference/admonitions/) & [Python Markdown](https://python-markdown.github.io/extensions/admonition/):
  
  ```
  !!! note
  
      This is a note alert block
  ```
  
  [Docusaurus](https://docusaurus.io/docs/markdown-features/admonitions):
  
  ```
  :::note
  
  This is a note alert block
  
  :::
  ```
  
  ### Additional Context
  
  - We could just reuse the [alert frontend components](https://docs.streamlit.io/develop/api-reference/status) that already exist in Streamlit
  - Remark/reype plugins:
     - [remark-github-beta-blockquote-admonitions](https://github.com/myl7/remark-github-beta-blockquote-admonitions) 
     - [remark-github-admonitions-to-directives](https://github.com/incentro-ecx/remark-github-admonitions-to-directives)
     - [rehype-github-alerts](https://github.com/chrisweb/rehype-github-alerts)