mediafoundation: Add support for AAC encoding

mediafoundation: Add support for AAC encoding

Add MediaFoundation AAC encoder element.

Before Windows 10, mono and stereo channels were supported audio channels
configuration by AAC encoder MFT. However, on Windows 10,
5.1 channels support was introduced.

To expose correct range of support format by this element
whatever the OS version is, this element will enumerate
all the supported format by the AAC encoder MFT
and then will configure sink/src templates while plugin init.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1280>