text: Title: Add a checkbox group widget
  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
  
  Add a new command to make it easy to create a group of checkboxes:
  
  <img width="129" alt="Image" src="https://github.com/user-attachments/assets/60eef5f6-9b42-4dc4-9b44-430916ca59e2" />
  
  ### Why?
  
  Simplify creating a group of checkboxes in a vertical or horizontal layout.
  
  ### How?
  
  This can be supported by a very similar API as `st.radio` and `st.multiselect`:
  
  ```python
  selected_options = st.checkbox_group(label, options, default=None, format_func=str, key=None, help=None, on_change=None, args=None, kwargs=None, *, max_selections=None, placeholder="Choose an option", disabled=False, label_visibility="visible", horizontal=False)
  ```
  
  The `horizontal` parameter allows to orient the checkbox group horizontally instead of vertically (same as `st.radio`)
  
  ### Additional Context
  
  _No response_