Add Nix cataloger (#1696)

* Add Basic Nix Cataloger

Signed-off-by: Julio Tain Sueiras <juliosueiras@gmail.com>

* Update nix def for the latest syft definition

Signed-off-by: Julio Tain Sueiras <juliosueiras@gmail.com>

* capture nix package files on pkg.NixStoreMetadata

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

* fix unit tests and linting

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

* update JSON schema

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

* address review comments

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

* Update syft/pkg/cataloger/nix/parse_nix_store_path_test.go

Co-authored-by: Florian Klink <flokli@flokli.de>
Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

* support unstable version conventions

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

* update json schema relative to main branch

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

* update syft json with v7.1.1 schema

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

* fix CLI tests

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

* remove extra continue statement

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

* add Nix to list of supported ecosystems

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

---------

Signed-off-by: Julio Tain Sueiras <juliosueiras@gmail.com>
Signed-off-by: Alex Goodman <alex.goodman@anchore.com>
Co-authored-by: Julio Tain Sueiras <juliosueiras@gmail.com>
Co-authored-by: Florian Klink <flokli@flokli.de>

syft/pkg/type.go

@@ -26,6 +26,7 @@ const (
 	JavaPkg               Type = "java-archive"
 	JenkinsPluginPkg      Type = "jenkins-plugin"
 	KbPkg                 Type = "msrc-kb"
+	NixPkg                Type = "nix"
 	NpmPkg                Type = "npm"
 	PhpComposerPkg        Type = "php-composer"
 	PortagePkg            Type = "portage"
@@ -51,6 +52,7 @@ var AllPkgs = []Type{
 	JavaPkg,
 	JenkinsPluginPkg,
 	KbPkg,
+	NixPkg,
 	NpmPkg,
 	PhpComposerPkg,
 	PortagePkg,
@@ -92,6 +94,8 @@ func (t Type) PackageURLType() string {
 		return packageurl.TypePyPi
 	case PortagePkg:
 		return "portage"
+	case NixPkg:
+		return "nix"
 	case NpmPkg:
 		return packageurl.TypeNPM
 	case RpmPkg:
@@ -151,6 +155,8 @@ func TypeByName(name string) Type {
 		return PortagePkg
 	case packageurl.TypeHex:
 		return HexPkg
+	case "nix":
+		return NixPkg
 	default:
 		return UnknownPkg
 	}