feat: Refactor database and configuration initialization

    Remove unused RPC_URL from .env.example
    Remove unnecessary backports.asyncio.runner dependency

Author: rakib4ggp

.env.example

@@ -1,4 +1,3 @@
-RPC_URL=
 PRIVATE_KEY=
 SECRET_KEY=
 DATABASE_URL=

requirements.txt

@@ -10,7 +10,6 @@ asn1crypto==1.5.1
 async-timeout==5.0.1
 asyncpg==0.31.0
 attrs==25.4.0
-backports.asyncio.runner==1.2.0
 base58==2.1.1
 bcrypt==5.0.0
 bitarray==3.8.0