feat: init and define database ops as interfaces to support multiple DBs

db/db-core/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "db-core"
+version = "0.1.0"
+edition = "2021"
+homepage = "https://mcaptcha.org"
+repository = "https://github.com/mCaptcha/mCaptcha"
+documentation = "https://mcaptcha.org/docs/"
+license = "AGPLv3 or later version"
+authors = ["realaravinth <realaravinth@batsense.net>"]
+
+[dependencies] 
+async-trait = "0.1.51"
+thiserror = "1.0.30"
+serde = { version = "1", features = ["derive"]}
+url = { version  = "2.2.2", features = ["serde"] }
+
+[features]
+default = []
+test = []
+
+[dev-dependencies]
+serde_json = "1"