[Site]: Add support for multi-rows and multi-column in docusaurus tables

### Current State

**Description of the current state/issue**:

Currently, Docusaurus doesn't support multi-rows or multi-column in tables.

**Link to the page**:

**Screenshots (if relevant)**:

Current table format:

| Header1 | Header 2| Header 3|
| --- | --- | --- |
| d1 | d2 | d3 |
| d4 | d5 | d6 |

### Desired State

**Description of the change you are proposing**:
Expected table format:

Layer 1
Layer 2
Layer 3




L1 Name
L2 Name A
L3 Name A


L3 Name B


L2 Name B
L3 Name C


L3 Name D


Layer Col 1
Layer Col

### Would you like to fix this issue?

Yes! Count me in

The issue names no files or tests. Start by locating the Docusaurus table-rendering entry point and checking how table markup is parsed; define the supported syntax for rowspan and colspan, then verify the example renders correctly in the website build and add coverage for the requested cases.

Written by the indexing model from the issue text.