Support for GZIP compression for client requests

[enricoboldrini]

To the aim of speeding up a bit the ingestion I have noticed that gzip compression is not available by default. It should minimize the size of uploads.

Steps to reproduce:

echo '{"name":"test","description":"test"}' > /tmp/test.json
gzip -c /tmp/test.json > /tmp/test.json.gz

// this will fail
curl -v -X POST "HOSTNAME/FROST-Server/v1.1/Things"
-H "Content-Type: application/json"
-H "Content-Encoding: gzip"
--data-binary @/tmp/test.json.gz

// while plain JSON will work
curl -v -X POST "HOSTNAME/FROST-Server/v1.1/Things"
-H "Content-Type: application/json"
--data-binary @/tmp/test.json

[hylkevds]

That's a great suggestion. A quick search shows that Tomcat doesn't support compression on data sent by clients though, so I'd have to build it into FROST directly.