Start adding metrics advanced (view) examples

[cijothomas]

Part of #1060

Changes

Add a metrics-advanced example, with 2 scenarios (rename, drop attributes) explained. If this direction is okay, I can add further scenarios. A lot of folks get confused by View, so hopefully these are useful examples.

Next steps would be to show how to change Histogram bounds (a common ask), drop an Instrument alltogether, changing temporality (default is cumulative, but a lot of backends need delta only) etc.

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (fb14199) 49.6% compared to head (f83710c) 49.6%.

Additional details and impacted files

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##            main   #1170   +/-   ##
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  Coverage   49.6%   49.6%           
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  Files        165     165           
  Lines      20522   20522           
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  Hits       10198   10198           
  Misses     10324   10324           

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