Open Telemetry: Adds open telemetry based versioning

[sourabh1007]

Description

Introducing versioning for open telemetry attributes, to make we are always backward compatible.

Environment Variable OTEL_SEMCONV_STABILITY_OPT_IN value supported :
database => Otel supported attributes. (right now, same as default, in future can be used to put any attribute change)
database/dup => Otel and appinsights attributes ( for those, who are moving from appinsightclassic to otel)
default => Otel Attributes (Breaking change, needs to be documented)
appinsightssdk => backward compatibility to appinsights.

Other minor changes,

1. Fix connection mode casing

{
              ConnectionMode.Direct => "direct",
              ConnectionMode.Gateway => "gateway",
              _ => throw new NotImplementedException()
          };

2. rename db.cosmosdb.item_count => db.cosmosdb.row_count

Code changes Overview

1. Introduced, TracesStabilityFactory.cs : Responsible to take care of version based attributes.
2. Updated Baseline Tests to have old and new both attributes in contract file.

Type of change

Please delete options that are not relevant.

• [] Bug fix (non-breaking change which fixes an issue)
• [] New feature (non-breaking change which adds functionality)
• [] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [] This change requires a documentation update

[FabianMeiswinkel]

LGTM overall but left two comments.

[FabianMeiswinkel]

LGTM - Thanks!

[kirankumarkolli]

Pending perf validation

[sourabh1007]

Pending perf validation

I will cover it is next PR