fix(operations): Make Operations a manual client [gax-java]

[miraleung]

This client has been actively supporting many APIs for a while, and contains manual logic to that effect. Removing the "Auto-generated" mentioned in comments will help us identify and support this as a manually-written client, and ensures we won't clobber it with a newly Gapic-generated one by mistake.

[elharo]

Is it still Beta?

[miraleung]

Removed for this and OperationSettings. I left them in for the stub classes (since they're everywhere across the dependent APIs), but LMK if we should remove them in one fell swoop.

[elharo]

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[codecov]

Codecov Report

Merging #1282 (b73ab36) into master (95a7dab) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #1282   +/-   ##
=========================================
  Coverage     79.19%   79.19%           
  Complexity     1235     1235           
=========================================
  Files           209      209           
  Lines          5378     5378           
  Branches        454      454           
=========================================
  Hits           4259     4259           
  Misses          939      939           
  Partials        180      180           

Impacted Files	Coverage Δ	Complexity Δ
.../java/com/google/longrunning/OperationsClient.java	73.33% <ø> (ø)	16.00 <0.00> (ø)
...ava/com/google/longrunning/OperationsSettings.java	29.03% <ø> (ø)	2.00 <0.00> (ø)
...ongrunning/stub/GrpcOperationsCallableFactory.java	37.50% <ø> (ø)	3.00 <0.00> (ø)
...om/google/longrunning/stub/GrpcOperationsStub.java	89.65% <ø> (ø)	11.00 <0.00> (ø)
...va/com/google/longrunning/stub/OperationsStub.java	16.66% <ø> (ø)	1.00 <0.00> (ø)
...oogle/longrunning/stub/OperationsStubSettings.java	73.83% <ø> (ø)	8.00 <0.00> (ø)

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[miraleung]

The following files are not formatted properly:

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Done.