Upgrade SwaggerUI to 3.23.0

[lorthirk]

This PR upgrades Swagger UI to 3.23.0. Also, Swagger is now injected in the REST API container at assembly phase rather than build phase.
Brief description of the PR.

Any side note on the changes made
SwaggerUI is imported from org.webjars:swagger-ui.

CQ Approved.

[codecov]

Codecov Report

Merging #2712 into develop will increase coverage by 2.44%.
The diff coverage is n/a.

@@              Coverage Diff              @@
##             develop    #2712      +/-   ##
=============================================
+ Coverage      51.82%   54.26%   +2.44%     
- Complexity      2836     3030     +194     
=============================================
  Files           1045     1045              
  Lines          29483    29483              
  Branches        2373     2373              
=============================================
+ Hits           15279    15999     +720     
+ Misses         13130    12389     -741     
- Partials        1074     1095      +21

Impacted Files	Coverage Δ	Complexity Δ
.../broker/core/plugin/KapuaSecurityBrokerFilter.java	75.87% <0%> (+1.26%)	0% <0%> (ø)	⬇️
...ain/java/org/eclipse/kapua/qa/common/TestBase.java	56.94% <0%> (+1.38%)	19% <0%> (ø)	⬇️
...n/java/org/eclipse/kapua/qa/common/Suppressed.java	51.72% <0%> (+1.72%)	12% <0%> (+1%)	⬆️
.../kapua/commons/model/query/AbstractKapuaQuery.java	76.19% <0%> (+2.38%)	0% <0%> (ø)	⬇️
...plugin/authentication/UserAuthenticationLogic.java	75.6% <0%> (+2.43%)	0% <0%> (ø)	⬇️
...iguration/metatype/XmlConfigPropertiesAdapter.java	23.82% <0%> (+2.55%)	0% <0%> (ø)	⬇️
.../step/definition/internal/JobStepPropertyImpl.java	70.37% <0%> (+3.7%)	10% <0%> (+1%)	⬆️
...a/org/eclipse/kapua/transport/mqtt/MqttClient.java	67.94% <0%> (+5.12%)	14% <0%> (+1%)	⬆️
...va/org/eclipse/kapua/commons/util/xml/XmlUtil.java	35.6% <0%> (+5.3%)	0% <0%> (ø)	⬇️
...step/definition/internal/JobStepDefinitionDAO.java	61.11% <0%> (+5.55%)	3% <0%> (+1%)	⬆️
... and 54 more

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