Prepare for Terraform 1.15 (alpha) release (#1348)

This PR prepares the repository for the Terraform 1.15 (alpha)
release.\n\nBootstrapped new directory for v1.15.x (alpha) based on
v1.14.x

Author: mildwonkey

content/terraform/v1.15.x (alpha)/data/cli-nav-data.json

@@ -0,0 +1,64 @@
+[
+  { "heading": "Terraform Internals" },
+  {
+    "title": "Overview", 
+    "path": ""
+   },
+  {
+    "title": "Credentials Helpers",
+    "path": "credentials-helpers"
+  },
+  {
+    "title": "Debugging Terraform",
+    "path": "debugging"
+  },
+  {
+    "title": "Module Registry Protocol",
+    "path": "module-registry-protocol"
+  },
+  {
+    "title": "Provider Network Mirror Protocol",
+    "path": "provider-network-mirror-protocol"
+  },
+  {
+    "title": "Provider Registry Protocol",
+    "path": "provider-registry-protocol"
+  },
+  {
+    "title": "Dependency Graph",
+    "path": "graph"
+  },
+  {
+    "title": "Login Protocol",
+    "path": "login-protocol"
+  },
+  {
+    "title": "JSON Output Format",
+    "path": "json-format"
+  },
+  {
+    "title": "Remote Service Discovery",
+    "path": "remote-service-discovery"
+  },
+  {
+    "title": "Provider Metadata",
+    "path": "provider-meta"
+  },
+  {
+    "title": "Functions Metadata",
+    "path": "functions-meta"
+  },
+  {
+    "title": "Machine Readable UI",
+    "path": "machine-readable-ui"
+  },
+  {
+    "title": "Archiving",
+    "path": "archiving",
+    "hidden": true
+  },
+  { "divider": true },
+  { "title": "Terraform CLI", "href": "/cli" },
+  { "divider": true },
+  { "title": "Configuration Language", "href": "/language" }
+]

content/terraform/v1.15.x (alpha)/data/internals-nav-data.json

@@ -0,0 +1,34 @@
+[
+  { "heading": "Introduction to Terraform" },
+  { "title": "What is Terraform?", "path": "" },
+  { "title": "Use Cases", "path": "use-cases" },
+  {
+    "title": "Get Started",
+    "href": "https://learn.hashicorp.com/collections/terraform/aws-get-started?utm_source=WEBSITE&utm_medium=WEB_IO&utm_offer=ARTICLE_PAGE&utm_content=DOCS"
+  },
+  { "title": "Terraform Editions", "path": "terraform-editions" },
+  { "title": "The Core Terraform Workflow", "path": "core-workflow" },
+  { 
+    "title": "Phases of Terraform Adoption", 
+    "routes": [
+      {"title": "Overview", "path": "phases"},
+      {"title": "Adopt", "path": "phases/adopt"},
+      {"title": "Collaborate", "path": "phases/collaborate"},
+      {"title": "Scale", "path": "phases/scale"},
+      {"title": "Govern", "path": "phases/govern"}
+    ]
+  },
+  {
+    "title": "Terraform vs. Alternatives",
+    "routes": [
+      { "title": "Overview", "path": "vs" },
+      { "title": "Chef, Puppet, etc.", "path": "vs/chef-puppet" },
+      {
+        "title": "CloudFormation, Heat, etc.",
+        "path": "vs/cloudformation"
+      },
+      { "title": "Boto, Fog, etc.", "path": "vs/boto" },
+      { "title": "Custom Solutions", "path": "vs/custom" }
+    ]
+  }
+]