Internalize majority of cmd package (#2533)

* internalize majority of cmd package and migrate integration tests

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* add internal api encoder

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* create internal representation of all formats

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* export capability to get default encoders

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

* restore test fixtures

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

---------

Signed-off-by: Alex Goodman <wagoodman@users.noreply.github.com>

cmd/syft/internal/test/integration/rust_audit_binary_test.go

@@ -0,0 +1,22 @@
+package integration
+
+import (
+	"testing"
+
+	"github.com/anchore/syft/syft/pkg"
+	"github.com/anchore/syft/syft/source"
+)
+
+func TestRustAudit(t *testing.T) {
+	sbom, _ := catalogFixtureImage(t, "image-rust-auditable", source.SquashedScope)
+
+	expectedPkgs := 2
+	actualPkgs := 0
+	for range sbom.Artifacts.Packages.Enumerate(pkg.RustPkg) {
+		actualPkgs += 1
+	}
+
+	if actualPkgs != expectedPkgs {
+		t.Errorf("unexpected number of Rust packages: %d != %d", expectedPkgs, actualPkgs)
+	}
+}