Update ProfileFile to support reading sub-properties.

[millems]

Sub-properties are those nested under another property. E.g.

[default]
s3 =
  endpoint_url = foo

Before this change, only s3 would be available, and would contain the raw string underneath the property. After this change, s3 remains the same, but foo can be retrieved through the property s3.endpoint_url.

This change also adds the property for endpoint_url and a convenience setter for profile content strings.

[sonarcloud[bot]]

Quality Gate passed

Issues
11 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud