Refactor Initial Script Structure

  Refactor App Installation Functions
  Enhance SSH Key Authentication Function
  Integrate User Input Handling
  Refactor Configuration Functions
  Improve Readability and Comments
  Fix Bug in Key Authentication Function
  Implement Auto-Delete of Script File
  Update README with Usage Instructions
  Update README with Badges and References

	modified:   README.md
	new file:   images/main_menu.png
	new file:   images/passwordless_sudo_enabled.png
	modified:   install.sh

Author: Decaded

README.md

@@ -1,4 +1,10 @@
-## Script I use to install essential apps on new Ubuntu systems
+## Script I use to configure new Ubuntu systems
+
+[![Code Size](https://img.shields.io/github/languages/code-size/Decaded/install-script)](https://github.com/Decaded/install-script)
+[![Open Issues](https://img.shields.io/github/issues/Decaded/install-script)](https://github.com/Decaded/install-script/issues)
+[![Open PRs](https://img.shields.io/github/issues-pr/Decaded/install-script)](https://github.com/Decaded/install-script/pulls)
+[![Last Commit](https://img.shields.io/github/last-commit/Decaded/install-script)](https://github.com/Decaded/install-script/commits)
+
 
 ### Functions
 
@@ -10,16 +16,28 @@
   - [firewalld](https://firewalld.org/)
     - After installation will open provided SSH port
   - [fail2ban](https://github.com/fail2ban/fail2ban)
+    - After installation will ask for configuration file;
+      - default one
+      - custom one (downloadable via url)
+      - [modified by me](https://gist.github.com/Decaded/4a2b37853afb82ecd91da2971726234a)
+  - [git](https://git-scm.com/)
+    - After installation prompts for first-time configuration
+  - [unattended-upgrades](https://help.ubuntu.com/community/AutomaticSecurityUpdates)
+  - [unzip](https://linux.die.net/man/1/unzip)
 
 - Option to disable password authentication and leave key-based only (as requested in [issue #1](https://github.com/Decaded/install-script/issues/1))
   - Asks for a public key that will be inserted into `$HOME/.ssh/authorized_keys`
+    - if the key already exist in the file, new entry will not be made
+  - `sshd_config` will be backed up to `/etc/ssh/sshd_config_decoscript.backup`
+    - this will enable option `6` in the menu: `Restore SSH Configuration`
 - Option to enable passwordless sudo access for the user running this script
   - Won't do anything if the user already has this enabled
 - Option to install a basic web server ([nginx](https://www.nginx.com/) & [php8.1](https://www.php.net/releases/8_1_0.php)-fpm)
   - Opens ports 80 and 443 TCP/UDP in the firewall
   - Removes [Apache2](https://httpd.apache.org/) if it exists
 - Option to install [Node Version Manager](https://github.com/nvm-sh/nvm)
 
+___
 ### Usage
 
 Download:
@@ -32,13 +50,19 @@ sudo chmod +x install.sh
 ```
 Run script:
 ```bash
-sudo ./install.sh
-```
-You can remove `install.sh` after installation is complete
-```bash
-rm install.sh
+./install.sh
 ```
+And just pick what you need from the menu:
 
+![Script in Action](images/main_menu.png)
+
+___
+### Contributing
+Contributions are welcome! If you find any issues or have suggestions for improvements, feel free to submit a [issue](https://github.com/Decaded/install-script/issues).
+
+___
 ### Disclaimer
-> I am by no means an expert in this field.
-> You use this script at your own risk.
+
+> I am by no means an expert in this field. You use this script at your own risk.
+
+___