feat: generate PASSWORD_HASH on the fly

* remove PASSWORD environment variable in favor of PASSWORD_HASH
* enhance password validity check server function
* update Dockerfile to include building a binary for generating hashed password
* update README with comprehensive Docker usage instructions hash generation

wg-password/PASSWORD.md

@@ -0,0 +1,25 @@
+# wg-password
+
+`wg-password` is a Rust binary that generates bcrypt password hashes for use with `wg-easy`, enhancing security by requiring passwords.
+
+## Features
+
+- Generate bcrypt password hashes.
+- Easily integrate with `wg-easy` to enforce password requirements.
+
+## Usage with Docker
+
+To generate a bcrypt password hash using Docker, run the following command:
+
+```sh
+docker run ghcr.io/wg-easy/wg-easy wgpw YOUR_PASSWORD
+PASSWORD_HASH='$2b$12$coPqCsPtcFO.Ab99xylBNOW4.Iu7OOA2/ZIboHN6/oyxca3MWo7fW' // litteraly YOUR_PASSWORD
+```
+
+## Important
+
+Make sure to enclose your password in single quotes when you run a linux host and *don't use double* `$`. [See](../How_to_generate_an_bcrypt_hash.md#generating-bcrypt-hash-from-an-script-file).
+
+## LICENSE
+
+[wg-easy license](../LICENSE)