[Exporter.Geneva] Update scopes

[utpilla]

Exporting scopes in GenevaExporter:

1. Export scopes which have a non-null key as individual columns (each key-value pair from the scopes is exported as its own column; these columns would also be taken into consideration when the CustomFields option is applied)
2. When using formatted strings for scopes, the templated string ("{OriginalFormat"}) will not be exported
3. GenevaExporter would not check for duplicate keys (if the scopes and log message together have any duplicate keys, they would all be exported)

Examples

1. Key is null

using (logger.BeginScope("MyScope"))
{
    logger.LogInformation("Hello from {food} {price}.", "artichoke", 3.99);
}

No scopes are exported in this case as there is no key provided for the scope.

2. Using formatted string in scopes

using (logger.BeginScope("MyInnerInnerScope with {FullName} and {age} of custom", "John Doe", 35))
{
    logger.LogInformation("Hello from {food} {price}.", "artichoke", 3.99);
}

Scopes exported:

FullName	age
"John Doe"	35

3. Using IEnumerable<KeyValuePair<string, object>> in scopes

using (logger.BeginScope(new List<KeyValuePair<string, object>>
{
    new KeyValuePair<string, object>("MyKey1", "MyValue1"),
    new KeyValuePair<string, object>("MyKey2", "MyValue2"),
}))
{
    logger.LogInformation("Hello from {food} {price}.", "artichoke", 3.99);
}

Scopes exported:

MyKey1	MyKey2
MyValue1	MyValue2

4. Duplicate Keys in scopes

using (logger.BeginScope(new List<KeyValuePair<string, object>>
{
    new KeyValuePair<string, object>("MyKey1", "MyValue1"),
    new KeyValuePair<string, object>("MyKey1", "MyValue1"),
}))
{
    logger.LogInformation("Hello from {food} {price}.", "artichoke", 3.99);
}

Scopes exported:

MyKey1	MyKey1
MyValue1	MyValue1

Please provide a brief description of the changes here.

For significant contributions please make sure you have completed the following items:

• Appropriate CHANGELOG.md updated for non-trivial changes

[codecov]

Codecov Report

Merging #736 (bb6700e) into main (7099b6f) will decrease coverage by 0.16%.
The diff coverage is 50.00%.

❗ Current head bb6700e differs from pull request most recent head 8d02885. Consider uploading reports for the commit 8d02885 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #736      +/-   ##
==========================================
- Coverage   77.55%   77.38%   -0.17%     
==========================================
  Files         176      176              
  Lines        5298     5294       -4     
==========================================
- Hits         4109     4097      -12     
- Misses       1189     1197       +8     

Impacted Files	Coverage Δ
...orter.Geneva/MsgPackExporter/MsgPackLogExporter.cs	90.51% <50.00%> (-3.56%)	⬇️

[utpilla]

Related to #389