add file contents cataloger

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

test/cli/power_user_cmd_test.go

@@ -51,6 +51,17 @@ func TestPowerUserCmdFlags(t *testing.T) {
 				assertSuccessfulReturnCode,
 			},
 		},
+		{
+			name: "content-cataloger-wired-up",
+			args: []string{"power-user", "docker-archive:" + getFixtureImage(t, "image-secrets")},
+			env: map[string]string{
+				"SYFT_CONTENTS_GLOBS": "/api-key.txt",
+			},
+			assertions: []traitAssertion{
+				assertInOutput(`"contents": "c29tZV9BcEkta0V5ID0gIjEyMzQ1QTdhOTAxYjM0NTY3ODkwMTIzNDU2Nzg5MDEyMzQ1Njc4OTAxMjM0NTY3ODkwMTIzNDU2Nzg5MCIK"`), // proof of the content cataloger
+				assertSuccessfulReturnCode,
+			},
+		},
 	}
 
 	for _, test := range tests {