Base: Add Terminal man page documentation

Author: https://github.com/bcoles
Commit: a50583ade1
Pull-request: https://github.com/SerenityOS/serenity/pull/4739

Base/usr/share/man/man1/Terminal.md

@@ -0,0 +1,23 @@
+## Name
+
+Terminal - Serenity terminal emulator
+
+## Synopsis
+
+```**sh
+$ Terminal [options]
+```
+
+## Description
+
+Terminal is a terminal emulator application for Serenity.
+
+## Options
+
+* `-e`: Execute this command inside the terminal
+
+## Examples
+
+```sh
+$ Terminal -e Shell
+```