Add Security:replaceUser support

[samniisan]

The new Security:replaceUser route has been added on JS/PHP side, this PR adds it on Android SDK as well.

Already documented in the following PR: https://github.com/kuzzleio/documentation/pull/264/files#diff-28f22657e9045419d382af6dbb7eff6b

fix https://github.com/kuzzleio/kuzzle-sdk/issues/21

Introduces

• Security:replaceUser support

[codecov-io]

Codecov Report

Merging #131 into 3.x will decrease coverage by <.01%.
The diff coverage is 90.9%.

@@            Coverage Diff             @@
##              3.x     #131      +/-   ##
==========================================
- Coverage   91.29%   91.29%   -0.01%     
==========================================
  Files          33       33              
  Lines        4100     4122      +22     
  Branches      391      392       +1     
==========================================
+ Hits         3743     3763      +20     
- Misses        253      255       +2     
  Partials      104      104

Impacted Files	Coverage Δ
src/main/java/io/kuzzle/sdk/security/Security.java	92.94% <90.9%> (-0.1%)	⬇️

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