Add powermock and fix tests

[Piotr-K8i]

Changes in this Pull Request:

• Add powermock and fix tests

Mandatory checks:

• [ ] latest changes were fetched from the upstream branch before creating this PR (branch is up to date)
• [ ] changes were tested manually
• [ ] unit tests were properly implemented
• [ ] communication about interdependent changes has been sent to the team (if applicable)
• [ ] respective Jenkins jobs were referenced in additional context section of this PR

OSCM Build References:

• [OSCM Build And Push job]()
• [OSCM Pull And Start job]()

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This change is 

[codecov[bot]]

Codecov Report

Merging #107 (2752f75) into master (29b8a16) will increase coverage by 1.00%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #107      +/-   ##
==========================================
+ Coverage   49.57%   50.57%   +1.00%     
==========================================
  Files         262      262              
  Lines       16703    16703              
  Branches     2190     2190              
==========================================
+ Hits         8280     8448     +168     
+ Misses       7859     7684     -175     
- Partials      564      571       +7     

Impacted Files	Coverage Δ
...c/main/java/org/oscm/app/aws/EC2Communication.java	70.60% <0.00%> (+1.35%)	:arrow_up:
...a/org/oscm/app/aws/controller/PropertyHandler.java	83.72% <0.00%> (+20.93%)	:arrow_up:
...java/org/oscm/app/aws/controller/EC2Processor.java	72.27% <0.00%> (+72.27%)	:arrow_up: