Configure logging in Docker image

[samisalkosuo]

Hi,

I'm using server as Docker image and it seems that for each request I get this in the Docker logs

Initial # of tokens in buckets: 1098788
Final # of tokens in buckets: 821091
Initial # of tokens in buckets: 513
Final # of tokens in buckets: 471
Bucket parseset-0 is 8 x 9 x 9
Bucket parseset-1 is 9 x 12 x 9
Bucket parseset-2 is 12 x 16 x 9
Bucket parseset-3 is 6 x 21 x 9
Bucket parseset-4 is 3 x 32 x 9
Initial # of tokens in buckets: 1098464
Final # of tokens in buckets: 820911
Initial # of tokens in buckets: 513
Final # of tokens in buckets: 471
Bucket parseset-0 is 8 x 9 x 9
Bucket parseset-1 is 9 x 12 x 9
Bucket parseset-2 is 12 x 16 x 9
Bucket parseset-3 is 6 x 21 x 9
Bucket parseset-4 is 3 x 32 x 9
 >>> 0/313 lemmas already filled before lemma cache module
 >>> 258/313 lemmatized with lemma cache
 >>> 0/313 unique tokens submitted to lemmatizer
172.17.0.1 - - [29/Mar/2019 10:31:00] "POST / HTTP/1.1" 200 -

When parsing a lot of texts, these logs unnecessarily fill out logs and, over time, may lead to unexpected problems if log files are not cleaned.

Using environment variable when starting Docker image would be good way to disable/configure logging.

@fginter, @jmnybl Big Thanks for providing Docker server! :-)

[fginter]

@samisalkosuo GPU support added for the docker images, as well as a lot of other improvements the logging is on the todo list, but time constraints apply atm