Generate PDF version of spec

[tdaede]

We should generate a downloadable PDF version of the 1.0.0 spec now that it is approved.

[sunghee-hwang]

There is no place to link IAMF spec in the current AOM home page (https://aomedia.org/av1-features/get-started/). It links for av1-related specs only.
I think that the AOM home page needs to be updated.

[sunghee-hwang]

@tdaede @cconcolato
As PR #775 has been merged, the link in IAMF PR indicates the working group draft.
https://aomedia.org/press%20releases/AOMedia-Advances-the-Audio-Innovation-Era/

The link (Immersive Audio Model and Formats (IAMF)) in IAMF PR needs to be updated to correctly indicate the final specification of IAMF v1.

[cconcolato]

IAMF needs to adopt the proposed new headers (latest-approved, latest-draft, ...)

[sunghee-hwang]

IAMF needs to adopt the proposed new headers (latest-approved, latest-draft, ...)

Now, it's ready.