feat: update syft license concept to complex struct (#1743)

this PR makes the following changes to update the underlying license model to have more expressive capabilities
it also provides some guarantee's surrounding the license values themselves

- Licenses are updated from string -> pkg.LicenseSet which contain pkg.License with the following fields:
- original `Value` read by syft
- If it's possible to construct licenses will always have a valid SPDX expression for downstream consumption
- the above is run against a generated list of SPDX license ID to try and find the correct ID
- SPDX concluded vs declared is added to the new struct
- URL source for license is added to the new struct
- Location source is added to the new struct to show where the expression was pulled from

syft/formats/common/cyclonedxhelpers/decoder_test.go

@@ -322,8 +322,7 @@ func Test_missingDataDecode(t *testing.T) {
 			},
 		},
 	})
-
-	assert.Len(t, pkg.Licenses, 0)
+	assert.Equal(t, pkg.Licenses.Empty(), true)
 }
 
 func Test_missingComponentsDecode(t *testing.T) {