Add ja4l_delta and ja4ls_delta derived fields to JA4 wireshark plugin…

Minor changes to some cases of how wmem strbufs are used. There is
minimal performance benefit, but hopefully improved code clarity.

Replace `wmem_strbuf_append_printf(buf, "%s", str)` with
`wmem_strbuf_append(buf, str)`. Replace
`wmem_strbuf_append_printf(buf, "%c", c)` with
`wmem_strbuf_append_c(buf, c)`. These changes avoid the overhead of
parsing a printf format string when it's redundant.

Use `wmem_strbuf_dup()` to duplicate a strbuf instead of
`wmem_strbuf_new(..., wmem_strbuf_get_str(oldbuf))` for slight
improvement in readability. (This change may cause a conflict
with #240 that is trivial to resolve.)

Use `wmem_strbuf_finalize()` when getting the final value of a strbuf.
For strings allocated in the file scope, this reduces the memory used by
the final string. The function is effectively a no-op for strings
allocated in the packet scope, but still makes clear to future readers
when a string is expected to undergo no further changes.

Update copyright year (#242)

Update README.md

Update README.md

* Add ja4d fingerprint

* Handle special cases

* Add pcap files for testing

* Handle empty options

* Remove pcap files

Added Google Cloud to vendor list

Remove unused functions (#231)