This commit switches UID hashing from md5 to a highway hash. It also
moves the salt value out of the file plugin - and makes it
installation-specific instead - it is moved to the global namespace.
There now are digest hash functions to make "static"
installation-specific hashes that are stable over workers available to
everyone; hashes can be 64, 128 or 256 bits in size.
Due to the fact that we switch the file hashing algorithm, all file
hashes change.
The underlyigng algorithm that is used for hashing is highwayhash-128,
which is significantly faster than md5.
- Any files where the total size was below the size of the
default bof_buffer size couldn't have stream analyzers successfully
attached because the bof_buffer never reached the full size
and was never flushed. This branch explicitly marks the buf_buffer
as full and flushes it when the file is being removed.