feat: absolute imports (#63)

* feat: go-like import style

jb now creates a directory structure inside of vendor/ that is similar to how go
does (github.com/grafana/jsonnet-libs). This is reflected in the final import
paths, which means they will be go-like

* refactor(spec/deps): named regexs

* feat: make goImportStyle configurable

Defaults to off, can be enabled in `jsonnetfile.json`

* fix: integration test

* doc: license headers

* fix(deps): remove GO_IMPORT_STYLE

not an option anymore, will always do so and symlink

* feat: symlink to legacy location

* feat: allow to disable legacy links

* fix(test): legacyImports in integration tests

* fix(spec): test

* fix: respect legacyName aliases

It was possible to alias packages by changing `name` previously.

While names are now absolute (and computed), legacy links should still respect
old aliases to avoid breaking code.

* fix(test): integration

* fix(init): keep legacyImports enabled for now

* feat: rewrite imports

adds a command to automatically rewrite imports from legacy to absolute style

* fix(tool): rewrite confused by prefixing packages

When a package was a prefix of another one, it broke.
Fixed that by using a proper regular expression. Added a test to make sure it
works as expected

* Update cmd/jb/init.go

* fix: exclude local packages from legacy linking

They actually still use the old style, which is fine. LegacyLinking
messed them up, but from now on it just ignores symlinks that match a localPackage.

spec/spec_test.go

@@ -18,6 +18,7 @@ import (
 	"encoding/json"
 	"testing"
 
+	"github.com/jsonnet-bundler/jsonnet-bundler/spec/deps"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -25,7 +26,6 @@ import (
 const jsonJF = `{
   "dependencies": [
     {
-      "name": "grafana-builder",
       "source": {
         "git": {
           "remote": "https://github.com/grafana/jsonnet-libs",
@@ -36,7 +36,7 @@ const jsonJF = `{
       "sum": "ELsYwK+kGdzX1mee2Yy+/b2mdO4Y503BOCDkFzwmGbE="
     },
     {
-      "name": "prometheus-mixin",
+      "name": "prometheus",
       "source": {
         "git": {
           "remote": "https://github.com/prometheus/prometheus",
@@ -46,29 +46,36 @@ const jsonJF = `{
       "version": "7c039a6b3b4b2a9d7c613ac8bd3fc16e8ca79684",
       "sum": "bVGOsq3hLOw2irNPAS91a5dZJqQlBUNWy3pVwM4+kIY="
     }
-  ]
+  ],
+  "legacyImports": false
 }`
 
 func testData() JsonnetFile {
 	return JsonnetFile{
-		Dependencies: map[string]Dependency{
-			"grafana-builder": {
-				Name: "grafana-builder",
-				Source: Source{
-					GitSource: &GitSource{
-						Remote: "https://github.com/grafana/jsonnet-libs",
-						Subdir: "grafana-builder",
+		LegacyImports: false,
+		Dependencies: map[string]deps.Dependency{
+			"github.com/grafana/jsonnet-libs/grafana-builder": {
+				Source: deps.Source{
+					GitSource: &deps.Git{
+						Scheme: deps.GitSchemeHTTPS,
+						Host:   "github.com",
+						User:   "grafana",
+						Repo:   "jsonnet-libs",
+						Subdir: "/grafana-builder",
 					},
 				},
 				Version: "54865853ebc1f901964e25a2e7a0e4d2cb6b9648",
 				Sum:     "ELsYwK+kGdzX1mee2Yy+/b2mdO4Y503BOCDkFzwmGbE=",
 			},
-			"prometheus-mixin": {
-				Name: "prometheus-mixin",
-				Source: Source{
-					GitSource: &GitSource{
-						Remote: "https://github.com/prometheus/prometheus",
-						Subdir: "documentation/prometheus-mixin",
+			"github.com/prometheus/prometheus/documentation/prometheus-mixin": {
+				LegacyNameCompat: "prometheus",
+				Source: deps.Source{
+					GitSource: &deps.Git{
+						Scheme: deps.GitSchemeHTTPS,
+						Host:   "github.com",
+						User:   "prometheus",
+						Repo:   "prometheus",
+						Subdir: "/documentation/prometheus-mixin",
 					},
 				},
 				Version: "7c039a6b3b4b2a9d7c613ac8bd3fc16e8ca79684",