Update lint scripts and CI configs.

This change adds a field* to disable the creation of STAP-A packets by the H264Payloader.

As per current behaviour, STAP-A packets are created by default. If the creation of STAP-A 
packets is disabled, NALUs of type 7 (SPS) and type 8 (PPS) will be packed as Single NAL Units.

This change can be a step to support packetization-mode=0 (single NALUs) in compliance with RFC6184.

Previously it would erroneously look at some of the reserved fields.

Implement AV1 bitstream format OBU header parser and utility functions
for OBU types.

Adds AV1Depacketizer which implements the Depacketizer interface for AV1

Now that we have separated the Packet/Depacketizer roles for
the AV1 codec, there is no need to include the videoDepacketizer
mixin in AV1Packet.

1. Rewrite the AV1 Payloader according to the spec.
2. AV1 bitstream reader.
3. Tries to optimize the use of the W field as much as possible to
    reduce the size of the packet.
4. Added tests around edge cases.