binary helper: drop analog channel support (submit samples to feed)

binary helper: drop analog channel support (submit samples to feed)

Remove the bv_send_analog_channel() routine and its data types. All
callers have migrated to the common feed queue API. Extracting numbers
from raw binary images remains the only use case for binary helpers.

Prefer read_u8() et al endianess aware readers over R8() preprocessor
macros. Reduce indentation in the switch() cases according to style.
Accept scale factor 0 to mean no scaling in addition to factor 1.
Update comments to avoid the redundant "binary blob" phrase.