use sed to translate optional -> oneof

[codeboten]

Using sed to substitute optional fields with oneof as suggested by @bogdandrutu: #4258 (comment)

@codeboten one option which I don't know if we thought/discuss about is to actually rely on oneof for the "optional/pointer":
optional fixed64 foo = 1 -> oneof foo_ { fixed64 foo = 1;}

This is a better alternative than #4750 as it allows us to continue using the proto generation as before.

Fixes #4258

[codecov]

Codecov Report

Merging #4929 (b297782) into main (67527b4) will increase coverage by 0.18%.
The diff coverage is 93.65%.

@@            Coverage Diff             @@
##             main    #4929      +/-   ##
==========================================
+ Coverage   90.85%   91.04%   +0.18%     
==========================================
  Files         180      178       -2     
  Lines       10622    10664      +42     
==========================================
+ Hits         9651     9709      +58     
+ Misses        755      738      -17     
- Partials      216      217       +1     

Impacted Files	Coverage Δ
model/pdata/metrics.go	94.23% <42.85%> (-3.71%)	⬇️
model/pdata/generated_metrics.go	97.29% <100.00%> (+0.15%)	⬆️
config/configtelemetry/configtelemetry.go	90.32% <0.00%> (ø)
config/configmapprovider/retrieved.go
config/configmapprovider/provider.go
service/telemetry.go	76.25% <0.00%> (+14.89%)	⬆️

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[bogdandrutu]

LGTM in general. I think this is a good compromise to move things forward with the optional, and unblock proto changes

[codeboten]

Output from sending min/max for histo/expohisto datapoints:

    metrics {
      name: "histogram"
      unit: "1"
      histogram {
        data_points {
          sum: 1234.0
          min: 10.0
          max: 694.1
        }
        aggregation_temporality: AGGREGATION_TEMPORALITY_CUMULATIVE
      }
    }
    metrics {
      name: "exponential-histogram"
      unit: "1"
      exponential_histogram {
        data_points {
          sum: 12345.0
          positive {
          }
          negative {
          }
          min: 105.0
          max: 694.15
        }
        aggregation_temporality: AGGREGATION_TEMPORALITY_DELTA
      }
    }

Will leave this in draft until open-telemetry/opentelemetry-proto#279 is merged

[codeboten]

@tigrannajaryan please take a look at this draft as you've reviewed the PR this replaces.

[tigrannajaryan]

LGTM

[tigrannajaryan]

Nit: this can check to see if (*ms.orig).Min_ != nil and use it without allocating a new one.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[codeboten]

Closing this, changes will be incorporated into #5064