Remove excess newlines from migration and GRPC modules

[prd-fox]

Continuation of #699

Applies the EmptyLineSeparator check to the migration and GRPC modules
No functional changes are part of this change.
One logic code change for the following:
- As the ConfigBuilder collects all forwarding keys from provided files, it will put into the final list instead of creating intermediate lists and adding them together. Result is the same in both cases.

• Removed excess newlines in code
• Added separation between class members for more readability (not to interfaces)

[codecov-io]

Codecov Report

Merging #724 into master will decrease coverage by <.01%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master     #724      +/-   ##
============================================
- Coverage     99.44%   99.44%   -0.01%     
  Complexity     1890     1890              
============================================
  Files           285      285              
  Lines          5621     5615       -6     
  Branches        284      284              
============================================
- Hits           5590     5584       -6     
  Misses            5        5              
  Partials         26       26

Impacted Files	Coverage Δ	Complexity Δ
.../java/com/quorum/tessera/client/GrpcP2pClient.java	100% <ø> (ø)	5 <0> (ø)	⬇️
...java/com/quorum/tessera/client/GrpcClientImpl.java	100% <ø> (ø)	7 <0> (ø)	⬇️
...om/quorum/tessera/client/GrpcP2pClientFactory.java	100% <ø> (ø)	3 <0> (ø)	⬇️
...in/java/com/quorum/tessera/grpc/p2p/Convertor.java	100% <ø> (ø)	6 <0> (ø)	⬇️
...rum/tessera/config/migration/LegacyCliAdapter.java	100% <ø> (ø)	19 <0> (ø)	⬇️
...um/tessera/grpc/api/APITransactionGrpcService.java	100% <ø> (ø)	8 <0> (ø)	⬇️
...um/tessera/config/builder/SslTrustModeFactory.java	100% <100%> (ø)	2 <1> (ø)	⬇️
...m/quorum/tessera/config/builder/ConfigBuilder.java	100% <100%> (ø)	38 <0> (ø)	⬇️
...orum/tessera/config/builder/JdbcConfigFactory.java	100% <100%> (ø)	4 <4> (ø)	⬇️

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