Added: Allow users to disable hardware keyboard shortcuts

The user can add `disable-hardware-keyboard-shortcuts=true` entry to `termux.properties` file to disable hardware keyboard shortcuts. The default value is `false`. Running `termux-reload-settings` command will also update the behaviour instantaneously if changed. Note that for `ctrl+alt+p` to work, you need to unset `shortcut.rename-session = ctrl + n`. https://wiki.termux.com/wiki/Terminal_Settings

Closes #1825