[BE Request] Create emitters for Tauri commands commonly invoked on FE

[shanimal08]

i think using an interval and emit on the BE is a little more reliable than constantly using invoke on the FE for data we need every second (and rather just have a listener on the FE when anything's changed)

if we could emit the data from the following tauri commands at an interval that'd be great. even better if it only emits if the data is different from the cached values :D

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• get_miner_metrics (already done in V2 branch, though it might not need to be a #[tauri::command] at all anymore?)
  • in addition to this, maybe split out the cached data further, sometimes CPU/GPU hashrates get stuck on loading because there's a cached version of SHA hashrate or base_node data
• get_tari_wallet_details
• get_transaction_history