add a mapping argument to existing collection.create methods

[scottinet]

What does this PR do ?

Allow Collection.create in Go, C++ and Java to handle a mapping argument, allowing to create new collections directly with a user-mapping specified.

Unit & functional tests have been added.

Other changes

• Add a SWIG template for Java to make it handle pointers to std::string (@jenow)

Boyscout

• Fix outdated test script name in the README file
• Fix a typo in functional test scenarios
• Add a ulimit configuration to elasticsearch's docker-compose, to allow it to run on computers with a number of opened files set with a low value

[codecov-io]

Codecov Report

Merging #183 into 1.x will increase coverage by 0.03%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##              1.x     #183      +/-   ##
==========================================
+ Coverage   88.88%   88.92%   +0.03%     
==========================================
  Files         244      244              
  Lines        4410     4416       +6     
==========================================
+ Hits         3920     3927       +7     
+ Misses        458      457       -1     
  Partials       32       32

Impacted Files	Coverage Δ
collection/create.go	100% <100%> (ø)	⬆️
kuzzle/queue.go	18.18% <0%> (-6.82%)	⬇️
realtime/join.go	78.37% <0%> (+5.4%)	⬆️
realtime/subscribe.go	77.14% <0%> (+5.71%)	⬆️

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