website: Remove the legacy v0.11 language documentation

We've been holding on to this snapshot of the old docs from the v0.11
branch ever since the v0.12 release as a courtesy to folks who are still
using Terraform v0.11, since until now we didn't have any way to serve
older versions' docs on the website alongside the current aside from
snapshotting it forward in this way.

However, our website framework now supports publishing multiple versions
at the same time and so the final resting place for these v0.11 docs will
be in the "v1.1" branch, whose content is serving as the documentation
for the "v1.1 and earlier" version selection on the website. While it does
still feel a little awkward to have v0.11 be a subsection of the v1.1
docs, this is at least more honest in that v0.11 _is_ earlier than v1.1,
whereas it's confusing and weird for it to appear under the "v1.2.x"
option and the other versions that will appear later.

In order to avoid breaking incoming links to the old docs we will deploy
this in conjunction with some additional redirects managed by the top-level
terraform-website repository, which will send all paths with the prefix
/language/configuration-0-11 to the equivalent path under
/language/v1.1.x/configuration-0-11 . That redirect rule must exist
outside of this repository because it's a bridge _between_ versions of
the website in this repository, rather than a link to other content within
the same version.

Author: apparentlymart

website/data/language-nav-data.json

@@ -1154,77 +1154,6 @@
       }
     ]
   },
-  {
-    "title": "Historical docs: 0.11 and Older",
-    "routes": [
-      { "title": "Overview", "path": "configuration-0-11" },
-      {
-        "title": "Load Order and Semantics",
-        "path": "configuration-0-11/load"
-      },
-      {
-        "title": "Configuration Syntax",
-        "path": "configuration-0-11/syntax"
-      },
-      {
-        "title": "Interpolation Syntax",
-        "path": "configuration-0-11/interpolation"
-      },
-      {
-        "title": "Overrides",
-        "path": "configuration-0-11/override"
-      },
-      {
-        "title": "Resources",
-        "path": "configuration-0-11/resources"
-      },
-      {
-        "title": "Data Sources",
-        "path": "configuration-0-11/data-sources"
-      },
-      {
-        "title": "Providers",
-        "href": "/language/providers"
-      },
-      {
-        "title": "Variables",
-        "path": "configuration-0-11/variables"
-      },
-      {
-        "title": "Outputs",
-        "path": "configuration-0-11/outputs"
-      },
-      {
-        "title": "Local Values",
-        "path": "configuration-0-11/locals"
-      },
-      {
-        "title": "Modules",
-        "path": "configuration-0-11/modules"
-      },
-      {
-        "title": "Terraform",
-        "path": "configuration-0-11/terraform"
-      },
-      {
-        "title": "Provisioners",
-        "href": "/language/resources/provisioners"
-      },
-      {
-        "title": "Providers",
-        "path": "configuration-0-11/providers",
-        "hidden": true
-      },
-      {
-        "title": "Terraform Push (deprecated)",
-        "path": "configuration-0-11/terraform-enterprise"
-      },
-      {
-        "title": "Environment Variables",
-        "path": "configuration-0-11/environment-variables"
-      }
-    ]
-  },
   { "divider": true },
   { "title": "Terraform Internals", "href": "/internals" },
   { "divider": true }