feat: support cyclonedx 1.5 - ValidationResult management

[mrizzi]

It looks like the changes in CycloneDX/cyclonedx-rust-cargo#639 to the validation error management introduced a hierarchy of errors through ValidationErrorsKind:

• ValidationErrorsKind::Struct and ValidationErrorsKind::List refer to further inner (and hence nested) ValidationResult
• ValidationErrorsKind::Field, ValidationErrorsKind::Enum and ValidationErrorsKind::Custom refer to the "final" validation error, i.e. ValidationError

Previously, in case of validation failure, i.e. ValidationResult::Failed, the failure's reasons were in a flat Vec structure containing FailureReason that allowed us to easily run through them for implementing the workaround for CycloneDX/cyclonedx-rust-cargo#737

This change in the validation errors management explains why the test parse_cyclonedx_valid_14_newline failed in PR-1721.
In fact the ValidationResult that came out of validation is something like:

ValidationResult { inner: {"components": Struct(ValidationResult { inner: {"inner": List({27: ValidationResult { inner: {"licenses": Struct(ValidationResult { inner: {"inner": List({0: ValidationResult { inner: {"license": Struct(ValidationResult { inner: {"license_identifier": Struct(ValidationResult { inner: {"Name": Enum(ValidationError { message: "NormalizedString contains invalid characters \\r \\n \\t or \\r\\n" })} })} })} }})} })} }})} })} }

In this PR I've added a recursive approach to traverse any ValidationResult in order to collect all of the distinct error messages.

With this fix, the tests are fine with no changes (also the parse_cyclonedx_invalid_serial_number one that failed on PR-1721 as well):

$ cargo test -p bombastic-model 
    Finished test [unoptimized + debuginfo] target(s) in 0.23s
     Running unittests src/lib.rs (target/debug/deps/bombastic_model-a5df717e66ea8ca4)

running 5 tests
test data::tests::parse_cyclonedx_without_serial_number ... ok
test data::tests::parse_cyclonedx_invalid_serial_number ... ok
test data::tests::parse_cyclonedx_valid_14 ... ok
test data::tests::parse_cyclonedx_valid_14_newline ... ok
test data::tests::parse_cyclonedx_valid_13 ... ok

[dejanb]

LGTM. Thanks