Don't stop on read-only mode for read-only storage workflows

Summary:
Fixes T11042. Currently, all `bin/storage` workflows stop if `cluster.read-only` is set:

```
$ ./bin/storage adjust
Usage Exception: Phabricator is currently in read-only mode. Use --force to override this mode.
```

However, some of them (`status`, `dump`, `databases`, etc) are read-only anyway and safe to run. Don't prompt in these cases.

Test Plan:
  - Set `cluster.read-only` to `true`.
  - Ran `bin/storage dump`, `bin/storage status`, etc. No longer received messages.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11042

Differential Revision: https://secure.phabricator.com/D15987

src/infrastructure/storage/management/workflow/PhabricatorStorageManagementDatabasesWorkflow.php

@@ -10,6 +10,10 @@ final class PhabricatorStorageManagementDatabasesWorkflow
       ->setSynopsis(pht('List Phabricator databases.'));
   }
 
+  protected function isReadOnlyWorkflow() {
+    return true;
+  }
+
   public function didExecute(PhutilArgumentParser $args) {
     $api     = $this->getAPI();
     $patches = $this->getPatches();

src/infrastructure/storage/management/workflow/PhabricatorStorageManagementDumpWorkflow.php

@@ -19,6 +19,10 @@ final class PhabricatorStorageManagementDumpWorkflow
         ));
   }
 
+  protected function isReadOnlyWorkflow() {
+    return true;
+  }
+
   public function didExecute(PhutilArgumentParser $args) {
     $api = $this->getAPI();
     $patches = $this->getPatches();

src/infrastructure/storage/management/workflow/PhabricatorStorageManagementProbeWorkflow.php

@@ -10,6 +10,10 @@ final class PhabricatorStorageManagementProbeWorkflow
       ->setSynopsis(pht('Show approximate table sizes.'));
   }
 
+  protected function isReadOnlyWorkflow() {
+    return true;
+  }
+
   public function didExecute(PhutilArgumentParser $args) {
     $console = PhutilConsole::getConsole();
     $console->writeErr(

src/infrastructure/storage/management/workflow/PhabricatorStorageManagementRenamespaceWorkflow.php

@@ -30,6 +30,10 @@ final class PhabricatorStorageManagementRenamespaceWorkflow
         ));
   }
 
+  protected function isReadOnlyWorkflow() {
+    return true;
+  }
+
   public function didExecute(PhutilArgumentParser $args) {
     $console = PhutilConsole::getConsole();
 

src/infrastructure/storage/management/workflow/PhabricatorStorageManagementShellWorkflow.php

@@ -10,9 +10,11 @@ final class PhabricatorStorageManagementShellWorkflow
       ->setSynopsis(pht('Launch an interactive shell.'));
   }
 
+  protected function isReadOnlyWorkflow() {
+    return true;
+  }
+
   public function execute(PhutilArgumentParser $args) {
-
-
     $api = $this->getAPI();
     list($host, $port) = $this->getBareHostAndPort($api->getHost());
 

src/infrastructure/storage/management/workflow/PhabricatorStorageManagementStatusWorkflow.php

@@ -10,6 +10,10 @@ final class PhabricatorStorageManagementStatusWorkflow
       ->setSynopsis(pht('Show patch application status.'));
   }
 
+  protected function isReadOnlyWorkflow() {
+    return true;
+  }
+
   public function didExecute(PhutilArgumentParser $args) {
     $api     = $this->getAPI();
     $patches = $this->getPatches();

src/infrastructure/storage/management/workflow/PhabricatorStorageManagementWorkflow.php

@@ -45,11 +45,15 @@ abstract class PhabricatorStorageManagementWorkflow
     return $this;
   }
 
+  protected function isReadOnlyWorkflow() {
+    return false;
+  }
 
   public function execute(PhutilArgumentParser $args) {
     $this->setDryRun($args->getArg('dryrun'));
     $this->setForce($args->getArg('force'));
 
+    if (!$this->isReadOnlyWorkflow()) {
       if (PhabricatorEnv::isReadOnly()) {
         if ($this->isForce()) {
           PhabricatorEnv::setReadOnly(false, null);
@@ -60,6 +64,7 @@ abstract class PhabricatorStorageManagementWorkflow
               'override this mode.'));
         }
       }
+    }
 
     return $this->didExecute($args);
   }