Translator module improvements

[Coduz]

This PR improves all kapua-translator modules.

Related Issue
None

Description of the solution adopted

• Translator location has been improved and a cache has been added to avoid looping trough the ServiceLoader for each Translator.getTranslatorFor(...)
• Exceptions have been refactored and moved to kapua-transport-api module to make them catchable from invoking code (replaces the general usage of carch (KapuaException e) {. Also exception messages have been added to prime a user-friendly message.
• Implementation of the translators have been improved and code has gone trough a cleanup, where possibile.
• A tons of Javadoc has been added.

Screenshots
None

Any side note on the changes made
Small fixes here and there where found.

[codecov]

Codecov Report

Merging #2876 into develop will increase coverage by 1.20%.
The diff coverage is 44.56%.

@@              Coverage Diff              @@
##             develop    #2876      +/-   ##
=============================================
+ Coverage      54.30%   55.50%   +1.20%     
- Complexity      2381     2556     +175     
=============================================
  Files           1040     1048       +8     
  Lines          22600    22783     +183     
  Branches        2039     2045       +6     
=============================================
+ Hits           12272    12645     +373     
+ Misses          9414     9189     -225     
- Partials         914      949      +35     

Impacted Files	Coverage Δ	Complexity Δ
...n/java/org/eclipse/kapua/message/KapuaPayload.java	50.00% <0.00%> (-50.00%)	0.00 <0.00> (ø)
...java/org/eclipse/kapua/KapuaRuntimeErrorCodes.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
...pua/service/device/call/message/DevicePayload.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
...a/service/device/call/kura/KuraDeviceCallImpl.java	70.68% <0.00%> (ø)	10.00 <0.00> (ø)
.../service/device/call/kura/app/SnapshotMetrics.java	0.00% <0.00%> (-85.72%)	0.00 <0.00> (-2.00)
.../service/device/call/message/kura/KuraChannel.java	90.00% <0.00%> (-10.00%)	9.00 <0.00> (-1.00)
...e/device/call/message/kura/app/KuraAppChannel.java	70.00% <0.00%> (-30.00%)	4.00 <0.00> (ø)
...ssage/kura/app/notification/KuraNotifyChannel.java	61.53% <0.00%> (-38.47%)	3.00 <1.00> (ø)
...ssage/kura/app/notification/KuraNotifyPayload.java	62.22% <ø> (+1.35%)	12.00 <0.00> (ø)
...l/message/kura/app/request/KuraRequestChannel.java	66.66% <0.00%> (-11.12%)	9.00 <0.00> (ø)
... and 142 more