Create a plan for implementing projects and also create the backend API. (#19)

Creates projects to organize tasks under. (Note the migration also contains the tables for creating folders for projects as well because adding foreign keys is a PITA in sqlite apparently).

Reviewed-on: #19
Co-authored-by: Drew Galbraith <drew@tiramisu.one>
Co-committed-by: Drew Galbraith <drew@tiramisu.one>

backend/.sqlx/query-93c31908b7409b034b143447cd8a1635f191f0abd4d547835c0f05aa403f96e0.json

@@ -0,0 +1,20 @@
+{
+  "db_name": "SQLite",
+  "query": "SELECT MAX(sort_order) as max_order FROM projects;",
+  "describe": {
+    "columns": [
+      {
+        "name": "max_order",
+        "ordinal": 0,
+        "type_info": "Integer"
+      }
+    ],
+    "parameters": {
+      "Right": 0
+    },
+    "nullable": [
+      true
+    ]
+  },
+  "hash": "93c31908b7409b034b143447cd8a1635f191f0abd4d547835c0f05aa403f96e0"
+}