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)

Remove unused functions (#231)

Remove all references to `wmem_packet_scope()`. This protects the plugin
against [planned improvements][1] to Wireshark memory management.

In `dissect_ja4()` and `init_ja4_data()`, directly replace
`wmem_packet_scope()` with `pinfo->pool`. The two are effectively the
same.

For `decode_http_lang()` and `wmem_list_to_str()`, add an argument to
the function signature which is a `wmem_allocator_t *`. Call
`decode_http_lang()` with `pinfo->pool` as the value for this argument.

`wmem_list_to_str()` only seems to be called by `ja4()` and `ja4_r()`,
and neither of those currently appear to be called by anything. For now,
I've made them pass `wmem_file_scope()` for the new argument of
`wmem_list_to_str()` since that's the scope they use for most of their
other work.

[1]: https://lists.wireshark.org/archives/wireshark-dev/202107/msg00052.html