Move Temporality enum opentelemetry_sdk::metrics::data:: to opentelemetry_sdk::metrics::

[cijothomas]

Earlier this Enum was used mostly by exporter authors, but this is now used by end users when setting up MeterProvider, so it makes to move it to metrics module directly.

[codecov]

Codecov Report

Attention: Patch coverage is 20.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 79.4%. Comparing base (a707bb9) to head (6261a0b).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
opentelemetry-stdout/src/metrics/exporter.rs	0.0%	2 Missing ⚠️
opentelemetry-otlp/src/exporter/http/mod.rs	0.0%	1 Missing ⚠️
opentelemetry-otlp/src/exporter/tonic/mod.rs	0.0%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #2289     +/-   ##
=======================================
- Coverage   79.4%   79.4%   -0.1%     
=======================================
  Files        122     122             
  Lines      20783   20783             
=======================================
- Hits       16506   16504      -2     
- Misses      4277    4279      +2     

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[utpilla]

Left a suggestion regarding the user experience when using the example code. Not a blocker.