Add SpeckDL compiler scaffold

- CLI entry point with yargs parsing for speckl-compile <file> --output-dir --bom-format
- TypeScript parser with AST types for all SpeckDL primitives
- Generator for PROV-O JSON-LD provenance graphs
- Generator for CycloneDX v1.6 BOMs
- Generator for SPDX 3.0.1 BOMs
- E2E test verifying RetryHandler.speck parsing and all output formats

All tests pass.

compiler/node_modules/stackback/test.js

@@ -0,0 +1,24 @@
+var assert = require('assert');
+var stackback = require('./');
+
+test('capture', function() {
+    var err = new Error();
+    var stack = stackback(err);
+    assert.equal(stack[0].getFileName(), __filename);
+});
+
+// calling stackback on the same error twice should work
+test('multiple calls', function() {
+    var err = new Error();
+    var stack1 = stackback(err);
+    var stack2 = stackback(err);
+    assert.equal(stack1[0].getFileName(), __filename);
+    assert.deepEqual(stack1, stack2);
+});
+
+test('string', function() {
+    var err = new Error();
+    stackback(err);
+    assert.equal(typeof err.stack, 'string');
+});
+