Add support for map fields in CycloneDX (XML and JSON)

[jonasagx]

What would you like to be added:
Map field support to cycloneDX

Why is this needed:
Golang bin metadata has a map with info of how a package was built.

Additional context:
Golang bin metadata has a map of values which is dropped when output format is cyclonedx (XML and JSON). Right now syft alerts that some data was skipped from the output:

$ syft (which syft) -o cyclonedx-xml | bat 
 ✔ Indexed /usr/local/bin/syft
 ✔ Cataloged packages      [215 packages]
[0000]  WARN skipping encoding of unsupported property: syft:metadata:goBuildSettings
[0000]  WARN skipping encoding of unsupported property: syft:metadata:goBuildSettings
[0000]  WARN skipping encoding of unsupported property: syft:metadata:goBuildSettings
[0000]  WARN skipping encoding of unsupported property: syft:metadata:goBuildSettings
[0000]  WARN skipping encoding of unsupported property: syft:metadata:goBuildSettings