feat(cache-simulation): add avg_age metric and update TTL experiment name

- Introduced `avg_age` metric to track the average age of cached objects during simulation.
- Updated experiment configuration name from "No Refresh (0.5s ttl)" to "No Refresh (5.0s ttl)".
- Updated Jupyter notebooks and related files to incorporate new metrics and change experiment labels.
- Modified experiment output CSV and PDF files to reflect the new `avg_age` metric and updated experiment details.

Signed-off-by: Tuan-Dat Tran <tuan-dat.tran@tudattr.dev>

aoi_cache_experiment_eval.ipynb

@@ -2,17 +2,20 @@
  "cells": [
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 1,
    "id": "ae430903-55a2-47ed-87c6-677b1fb44198",
    "metadata": {},
    "outputs": [],
    "source": [
-    "from enum import Enum"
+    "from enum import Enum\n",
+    "import os\n",
+    "import pandas as pd\n",
+    "import matplotlib.pyplot as plt"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 2,
    "id": "9d6920fc-8633-4754-a762-ece23af18877",
    "metadata": {},
    "outputs": [],
@@ -23,12 +26,12 @@
     "    RANDOM_EVICTION = 2\n",
     "\n",
     "\n",
-    "DATABASE_OBJECTS = 100 # Number of objects in the database\n"
+    "DATABASE_OBJECTS = 100 # Number of objects in the database"
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 33,
+   "execution_count": 3,
    "id": "9b8c0686-1bab-47a4-9f9f-e5a11167ea8c",
    "metadata": {},
    "outputs": [],
@@ -54,7 +57,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 49,
+   "execution_count": 4,
    "id": "5be1df01-5dc8-43fe-a597-72ba76eefc0f",
    "metadata": {},
    "outputs": [
@@ -75,7 +78,7 @@
        "  'data': {'hit_rate': 0.7175225869007572, 'avg_age': 2.4791552890507336}}]"
       ]
      },
-     "execution_count": 49,
+     "execution_count": 4,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -93,7 +96,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 52,
+   "execution_count": 5,
    "id": "26030d03-b970-4e88-9c9a-e96ef79181c6",
    "metadata": {},
    "outputs": [