Revisit sphinx-autoapi templates

Ensure that:

[x] Object name is not included in method or property description. Can only be fixed via CSS to ensure xref are still valid and unique. Implemented in #358. Example:
```
  FooObject.bar_property -> bar_property
```
[x] Create "api" group in external dependencies. Implemented in #355
[x] Use Nerd Fonts for rendering symbols in toctree. Implemented in #362
[x] Ensure typehints are using "short" qualification when rendering. Example:
```
  def function(foo: ansys.library.core.Foo) -> def function(foo: Foo)
```
Default "sphinx-autoapi" templates for "method.rst" are using the Sphinx Python Domain to avoid enabling additional extensions. Consider using "autodoc" rather than .. py:method::.

See typehints_fully_qualified = False from https://github.com/tox-dev/sphinx-autodoc-typehints See autodoc_typehints_format = "short" from https://www.sphinx-doc.org/en/master/usage/extensions/autodoc.html #358

ansys / ansys-sphinx-theme