demux: ogg: rewrite pts and pts computation (fix #9828)

- Previous algorithm was unable to guess the first packet
pts because of ogg design (some codecs/opus/vorbis have total
sample at page granule and only granule on last packet. You
then need to compute first packet pts backward using packets
duration).
So we were stuck either assuming a start at pts/pcr zero, or
be unable to handle ogg streaming (non zero start) correctly,
or had to always drop the 0..N-1 packets for first page.
We need libvorbis to correcly compute those durations (code
is far more complex than opus's one).
- Refactorized to discard the tons of cases appended
with each new codec.
- lots of other fixes in many places
demux: ogg: add more divbyzero checks and fix oggds ones

cid 1191737