Make Rpc setters chainable in RPC generator

[JulianKast]

Fixes #1463

This PR is ready for review.

Risk

This PR makes no API changes.

Testing Plan

• I have verified that I have not introduced new warnings in this PR (or explain why below)
• I have run the unit tests with this PR
• I have tested this PR against Core and verified behavior (if applicable, if not applicable, explain why below).
• I have tested Android, Java SE, and Java EE

Unit Tests

N/A

Core Tests

Tested using the RPC Generator to make sure it generated structs and functions correctly, as well as making sure setters and chainable.

Summary

Edited function_template.java and struct_template.java to make RPC setters chainable when it generates Rpc's

Changelog

Enhancements

• RPC generator will now make RPC setters chainable

CLA

• I have signed the CLA

[codecov]

Codecov Report

Merging #1525 into release/RC_5.0.0 will decrease coverage by 0.01%.
The diff coverage is n/a.

@@                  Coverage Diff                   @@
##             release/RC_5.0.0    #1525      +/-   ##
======================================================
- Coverage               56.15%   56.14%   -0.02%     
  Complexity               4991     4991              
======================================================
  Files                     515      515              
  Lines                   22272    22272              
  Branches                 2768     2768              
======================================================
- Hits                    12507    12504       -3     
- Misses                   8833     8834       +1     
- Partials                  932      934       +2     

Impacted Files	Coverage Δ	Complexity Δ
...tdevicelink/managers/audio/AudioDecoderCompat.java	70.00% <0.00%> (-3.34%)	3.00% <0.00%> (ø%)
...com/smartdevicelink/util/MediaStreamingStatus.java	63.80% <0.00%> (-0.96%)	17.00% <0.00%> (ø%)

[RHenigan]

The updated methods need to "return this;"