Drop support for asciidoctor outside of docker (#611)

We initially supported asciidoctor in the same way that the docs build
supported everything else: by copying the source into the repo. Now that
we have docker to resolve our dependencies we don't need to do that. This
blasts asciidoctor from the repo and the infrastructure for copying it
locally.

Author: nik9000

build_docs.pl

@@ -104,6 +104,10 @@ sub build_local {
 
     _guess_opts_from_file($index);
 
+    if ( $Opts->{asciidoctor} && !$running_in_standard_docker ) {
+        die "--asciidoctor is only supported by build_docs and not by build_docs.pl";
+    }
+
     if ( $Opts->{single} ) {
         $dir->rmtree;
         $dir->mkpath;
@@ -605,7 +609,6 @@ sub init_env {
 
     $ENV{PATH}
         = dir('resources/asciidoc-8.6.8/')->absolute
-        . ':' . dir('resources/asciidoctor/bin')->absolute
         . ":$FindBin::RealBin:"
         . $ENV{PATH};
 

resources/asciidoctor/.bundle/config

@@ -7,4 +7,4 @@ MAKEFLAGS += --silent
 .PHONY: check
 check:
 	rspec
-	rubocop --cache false lib spec
+	rubocop --cache false

resources/asciidoctor/.bundle/prod/config

@@ -1,17 +1,3 @@
-The `bin` and `vendor` directories contain a fully checked out copy of
-asciidoctor. You should be able to update it by changing the `Gemfile` and
-running:
-
-```
-cd resources/asciidoctor
-BUNDLE_APP_CONFIG=.bundle/prod bundle install --standalone --no-cache
-```
-
-The `lib` directory contains extensions to asciidoctor that are required for
-Elastic's docs. You can test them with:
-
-```
-cd resources/asciidoctor
-bundle install
-./build/bin/rspec
-```
+These are Elastic's extensions to Asciidoctor! The `lib` directory contains
+the actual extensions and the spec directory contains the tests. You can run
+the tests with `build_docs --self-test`.