app/frames: initial support

app/frames: initial support

The idea of stream frames is that the applayer parsers can tag PDUs and
other arbitrary frames in the stream while parsing. These frames can then
be inspected from the rule language. This will allow rules that are more
precise and less costly.

The frames are stored per direction in the `AppLayerParserState` and will only
be initialized when actual frames are in use. The per direction storage has a
fixed size static portion and dynamic support for a larger number. This is done
for effeciency.

When the Stream Buffer slides, frames are updated as they use offsets relative
to the stream. A negative offset is used for frames that started before the
current window.

Frames have events to inspect/log parser errors that don't fit the TX model.

Frame id starts at 1. So implementations can keep track of frame ids where 0
is not set.

Frames affect TCP window sliding. The frames keep a "left edge" which
signifies how much data to keep for frames that are still in progress.