Add SPDX support (#445)

* add initial spdx support

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

* expose FileOwner and use in SPDX presenter

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

* add initial json support for SPDX

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

* add remaining package fields

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

* add spdx license list generation + tests

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

* keep fileOwner unexported from pkg

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

* restore cli test util

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

* add external refs to spdx tag-value format

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

* add golang support to CPE generation

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

* use tag-value format as default "spdx" format flavor

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

* add tests around spdx presenters + refactor presenter tests

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

* add bouncer exception for spdx tools-golang repo

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

* remove spdx model questions

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

.bouncer.yaml

@@ -6,4 +6,12 @@ permit:
   - ISC
 ignore-packages:
   # packageurl-go is released under the MIT license located in the root of the repo at /mit.LICENSE
-  - github.com/package-url/packageurl-go
+  - github.com/package-url/packageurl-go
+
+  # from: https://github.com/spdx/tools-golang/blob/main/LICENSE.code
+  # The tools-golang source code is provided and may be used, at your option,
+  # under either:
+  # * Apache License, version 2.0 (Apache-2.0), OR
+  # * GNU General Public License, version 2.0 or later (GPL-2.0-or-later).
+  # (we choose Apache-2.0)
+  - github.com/spdx/tools-golang