Add instrumentation for gorm

[MrAlias]

This new module instruments the github.com/jinzhu/gorm package. The instrumentation wraps the sql.DB used by "github.com/jinzhu/gorm".DB with the existing instrumentation from github.com/signalfx/splunk-otel-go/instrumentation/database/sql/splunksql.

• Comply with OpenTelemetry database semantic conventions (done using the already compliant github.com/signalfx/splunk-otel-go/instrumentation/database/sql/splunksql instrumentation)
• Package documentation
• Exported objects are documented
• Tests and linting are passing
• Includes dependabot config
• Library added to README.md

[codecov-commenter]

Codecov Report

Merging #98 (d2b9240) into main (96b06ee) will increase coverage by 0.24%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #98      +/-   ##
==========================================
+ Coverage   81.07%   81.32%   +0.24%     
==========================================
  Files          21       22       +1     
  Lines         856      862       +6     
==========================================
+ Hits          694      701       +7     
+ Misses        130      128       -2     
- Partials       32       33       +1     

Flag	Coverage Δ
Linux	80.16% <100.00%> (+0.25%)	⬆️
Windows	80.62% <100.00%> (+0.25%)	⬆️
macOS	79.46% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...mentation/github.com/jinzhu/gorm/splunkgorm/sql.go	100.00% <100.00%> (ø)
instrumentation/database/sql/splunksql/config.go	83.80% <0.00%> (+0.70%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 96b06ee...d2b9240. Read the comment docs.

[pellared]

I think it only misses a line in the CHANGELOG