Promote exponential histogram data interfaces to stable package

[jack-berg]

Exponential histograms have been marked stable 🎉!

This PR moves the data model interfaces to io.opentelemetry.sdk.metrics.data, the first in a series of steps for metrics to be stable in the java SDK.

[codecov]

Codecov Report

Base: 91.03% // Head: 91.03% // Decreases project coverage by -0.00% ⚠️

Coverage data is based on head (b6ceb73) compared to base (e9c38b6).
Patch coverage: 62.50% of modified lines in pull request are covered.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #5120      +/-   ##
============================================
- Coverage     91.03%   91.03%   -0.01%     
+ Complexity     4875     4873       -2     
============================================
  Files           549      547       -2     
  Lines         14437    14434       -3     
  Branches       1390     1390              
============================================
- Hits          13143    13140       -3     
  Misses          894      894              
  Partials        400      400              

Impacted Files	Coverage Δ
.../metrics/ExponentialHistogramBucketsMarshaler.java	100.00% <ø> (ø)
...etrics/ExponentialHistogramDataPointMarshaler.java	100.00% <ø> (ø)
...al/otlp/metrics/ExponentialHistogramMarshaler.java	100.00% <ø> (ø)
.../opentelemetry/exporter/prometheus/Serializer.java	86.68% <0.00%> (ø)
.../aggregator/DoubleExponentialHistogramBuckets.java	83.33% <ø> (ø)
...l/aggregator/ExponentialHistogramAccumulation.java	100.00% <ø> (ø)
...l/data/ImmutableExponentialHistogramPointData.java	100.00% <ø> (ø)
...sdk/metrics/internal/data/ImmutableMetricData.java	100.00% <ø> (ø)
.../io/opentelemetry/sdk/metrics/data/MetricData.java	81.81% <33.33%> (-7.66%)	⬇️
...xporter/internal/otlp/metrics/MetricMarshaler.java	93.61% <100.00%> (-0.14%)	⬇️
... and 3 more

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