Refactor project structure to organize APIs (#24)

* Refactor project structure "api"
* fix bug conversione delle valute fiat in stablecoin in BinanceWrapper
* Refactor: WrapperHandler for managing API wrappers with retry logic; update related modules and tests
* Refactor: Update ProductInfo and Price classes to include aggregation methods; remove standalone aggregation functions
* fix docs

src/app/api/social/reddit.py

@@ -0,0 +1,67 @@
+import os
+from praw import Reddit # type: ignore
+from praw.models import Submission # type: ignore
+from app.api.base.social import SocialWrapper, SocialPost, SocialComment
+
+
+MAX_COMMENTS = 5
+# metterne altri se necessario.
+# fonti: https://lkiconsulting.io/marketing/best-crypto-subreddits/
+SUBREDDITS = [
+    "CryptoCurrency", 
+    "Bitcoin",
+    "Ethereum",
+    "CryptoMarkets",
+    "Dogecoin",
+    "Altcoin",
+    "DeFi",
+    "NFT",
+    "BitcoinBeginners",
+    "CryptoTechnology",
+    "btc" # alt subs of Bitcoin
+]
+
+
+def extract_post(post: Submission) -> SocialPost:
+    social = SocialPost()
+    social.time = str(post.created)
+    social.title = post.title
+    social.description = post.selftext
+
+    for top_comment in post.comments:
+        comment = SocialComment()
+        comment.time = str(top_comment.created)
+        comment.description = top_comment.body
+        social.comments.append(comment)
+
+        if len(social.comments) >= MAX_COMMENTS:
+            break
+    return social
+
+class RedditWrapper(SocialWrapper):
+    """
+    A wrapper for the Reddit API using PRAW (Python Reddit API Wrapper).
+    Requires the following environment variables to be set:
+    - REDDIT_API_CLIENT_ID
+    - REDDIT_API_CLIENT_SECRET
+
+    You can get them by creating an app at https://www.reddit.com/prefs/apps
+    """
+
+    def __init__(self):
+        client_id = os.getenv("REDDIT_API_CLIENT_ID")
+        assert client_id, "REDDIT_API_CLIENT_ID environment variable is not set"
+
+        client_secret = os.getenv("REDDIT_API_CLIENT_SECRET")
+        assert client_secret, "REDDIT_API_CLIENT_SECRET environment variable is not set"
+
+        self.tool = Reddit(
+            client_id=client_id,
+            client_secret=client_secret,
+            user_agent="upo-appAI",
+        )
+        self.subreddits = self.tool.subreddit("+".join(SUBREDDITS))
+
+    def get_top_crypto_posts(self, limit: int = 5) -> list[SocialPost]:
+        top_posts = self.subreddits.top(limit=limit, time_filter="week")
+        return [extract_post(post) for post in top_posts]