feat: Implement interfaces and utilities needed for Pub/Sub Lite Kafka shim

[dpcollins-google]

Also run mvn fmt:format

[codecov]

Codecov Report

Merging #276 into master will decrease coverage by 0.81%.
The diff coverage is 36.27%.

@@ Coverage Diff @@ ## master #276 +/- ## ============================================ - Coverage 71.73% 70.91% -0.82%  - Complexity 771 780 +9  ============================================ Files 141 145 +4 Lines 4136 4243 +107 Branches 215 216 +1 ============================================ + Hits 2967 3009 +42  - Misses 1044 1107 +63  - Partials 125 127 +2 

Impacted Files	Coverage Δ	Complexity Δ
...le/cloud/pubsublite/kafka/KafkaExceptionUtils.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
.../google/cloud/pubsublite/kafka/PubsubLiteNode.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...oogle/cloud/pubsublite/internal/ExtractStatus.java	44.44% <30.43%> (-33.34%)	4.00 <1.00> (-2.00)
...com/google/cloud/pubsublite/kafka/LiteHeaders.java	34.78% <34.78%> (ø)	4.00 <4.00> (?)
...oogle/cloud/pubsublite/kafka/RecordTransforms.java	84.61% <84.61%> (ø)	3.00 <3.00> (?)
...d/pubsublite/internal/BufferingPullSubscriber.java	85.71% <0.00%> (+3.66%)	8.00% <0.00%> (+4.00%)

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