pass through whether Periphery docker daemon connection is ok

bin/periphery/src/api/mod.rs

@@ -238,6 +238,7 @@ impl Resolve<Args> for PollStatus {
         container_terminals_disabled: config
           .disable_container_terminals,
         stats_polling_rate: config.stats_polling_rate,
+        docker_connected: docker_client().load().is_some(),
       },
       system_info: stats_client.info.clone(),
       system_stats,

client/core/rs/src/entities/server.rs

@@ -356,6 +356,8 @@ pub struct PeripheryInformation {
   pub container_terminals_disabled: bool,
   /// The rate the system stats are being polled from the system
   pub stats_polling_rate: Timelength,
+  /// Whether Periphery is successfully connected to docker daemon.
+  pub docker_connected: bool,
 }
 
 /// Info about an active terminal on a server.