observatory herald (#30)

* WIP: initial commit for observatory herald

* Plugin error handling refactor

* make error window non-modal

* tidy up plugin error handling

* first pass for basic herald functionality

* corrections for linux env

* Use FNV hash directly instead of managing through dictionary/index file

* resolve audio queuing issue, switch to personal NetCoreAudio fork

* merge cleanup

* add enable setting, populate defaults

* framework xml doc update

* Adjust settings, add style selection, replace locale with demonym in dropdown list.

* Test is position is on screen before saving/loading.

* use a default that's actually in the list

ObservatoryHerald/HeraldSettings.cs

@@ -0,0 +1,29 @@
+using Observatory.Framework;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Observatory.Herald
+{
+    public class HeraldSettings
+    {
+        [SettingDisplayName("API Key Override: ")]
+        public string AzureAPIKeyOverride { get; set; }
+
+        [SettingDisplayName("Voice")]
+        [SettingBackingValue("SelectedVoice")]
+        [System.Text.Json.Serialization.JsonIgnore]
+        public Dictionary<string, object> Voices { get; internal set; }
+
+        [SettingIgnore]
+        public string SelectedVoice { get; set; }
+
+        [System.Text.Json.Serialization.JsonIgnore]
+        public Action Test { get; internal set; }
+
+        [SettingDisplayName("Enabled")]
+        public bool Enabled { get; set; }
+    }
+}