Initial gem dependencies (#4229)

These are immediate dependencies, and include many circular dependencies, largely amongst the Atom gems, as indicated by cmake

Signed-off-by: AMZN-alexpete <26804013+AMZN-alexpete@users.noreply.github.com>

Gems/AssetMemoryAnalyzer/gem.json

@@ -5,9 +5,18 @@
     "origin": "Open 3D Engine - o3de.org",
     "type": "Code",
     "summary": "The Asset Memory Analyzer Gem provides tools to profile asset memory usage in Open 3D Engine through ImGUI (Immediate Mode Graphical User Interface).",
-    "canonical_tags": ["Gem"],
-    "user_tags": ["Debug", "Utility", "Tools"],
+    "canonical_tags": [
+        "Gem"
+    ],
+    "user_tags": [
+        "Debug",
+        "Utility",
+        "Tools"
+    ],
     "icon_path": "preview.png",
     "requirements": "",
-    "documentation_url": "https://o3de.org/docs/user-guide/gems/reference/debug/asset-memory-analyzer/"
+    "documentation_url": "https://o3de.org/docs/user-guide/gems/reference/debug/asset-memory-analyzer/",
+    "dependencies": [
+        "ImGui"
+    ]
 }