Give NamedComponentReader access to read plugins directories (elastic#123431)

The NamedComponentReader reads a file created upon plugin installation
for stable plugins from the plugin installation dir. This commit passes
the plugins directory through to entitlements and grants server access.

Author: rjernst

libs/entitlement/src/main/java/org/elasticsearch/entitlement/bootstrap/EntitlementBootstrap.java

@@ -41,6 +41,7 @@ public record BootstrapArgs(
         Path[] sharedRepoDirs,
         Path configDir,
         Path libDir,
+        Path pluginsDir,
         Path logsDir,
         Path tempDir,
         Path pidFile,
@@ -58,6 +59,7 @@ public record BootstrapArgs(
             requireNonNull(sharedRepoDirs);
             requireNonNull(configDir);
             requireNonNull(libDir);
+            requireNonNull(pluginsDir);
             requireNonNull(logsDir);
             requireNonNull(tempDir);
             requireNonNull(suppressFailureLogClasses);
@@ -82,6 +84,7 @@ public static BootstrapArgs bootstrapArgs() {
      * @param sharedRepoDirs       shared repository directories for Elasticsearch
      * @param configDir      the config directory for Elasticsearch
      * @param libDir         the lib directory for Elasticsearch
+     * @param pluginsDir     the directory where plugins are installed for Elasticsearch
      * @param tempDir        the temp directory for Elasticsearch
      * @param logsDir        the log directory for Elasticsearch
      * @param pidFile        path to a pid file for Elasticsearch, or {@code null} if one was not specified
@@ -96,6 +99,7 @@ public static void bootstrap(
         Path[] sharedRepoDirs,
         Path configDir,
         Path libDir,
+        Path pluginsDir,
         Path logsDir,
         Path tempDir,
         Path pidFile,
@@ -114,6 +118,7 @@ public static void bootstrap(
             sharedRepoDirs,
             configDir,
             libDir,
+            pluginsDir,
             logsDir,
             tempDir,
             pidFile,

libs/entitlement/src/main/java/org/elasticsearch/entitlement/initialization/EntitlementInitialization.java

@@ -152,6 +152,7 @@ private static PolicyManager createPolicyManager() {
         Collections.addAll(
             serverModuleFileDatas,
             // Base ES directories
+            FileData.ofPath(bootstrapArgs.pluginsDir(), READ),
             FileData.ofPath(bootstrapArgs.configDir(), READ),
             FileData.ofPath(bootstrapArgs.logsDir(), READ_WRITE),
             FileData.ofRelativePath(Path.of(""), DATA, READ_WRITE),

server/src/main/java/org/elasticsearch/bootstrap/Elasticsearch.java

@@ -248,6 +248,7 @@ private static void initPhase2(Bootstrap bootstrap) throws IOException {
                 nodeEnv.repoDirs(),
                 nodeEnv.configDir(),
                 nodeEnv.libDir(),
+                nodeEnv.pluginsDir(),
                 nodeEnv.logsDir(),
                 nodeEnv.tmpDir(),
                 args.pidFile(),