fix CLI: proper ASCII banner, __main__.py entry point

- replace block unicode art with figlet slant font
- add __main__.py so python3 -m euri_mklive works
- fix raw string banner (ANSI escapes now work)

euri_mklive/__main__.py

@@ -0,0 +1,3 @@
+from .cli import cli
+
+cli()

euri_mklive/cli.py

@@ -13,15 +13,11 @@ from .rootfs import build, cleanup
 from .iso import generate
 from .distros import REGISTRY
 
-BANNER = r"""
-\033[1;36m
-  ██╗███╗   ██╗████████╗██╗     ██████╗
-  ██║████╗  ██║╚══██╔══╝██║     ██╔══██╗
-  ██║██╔██╗ ██║   ██║   ██║     ██████╔╝
-  ██║██║╚██╗██║   ██║   ██║     ██╔══██╗
-  ██║██║ ╚████║   ██║   ███████╗██║  ██║
-  ╚═╝╚═╝  ╚═══╝   ╚═╝   ╚══════╝╚═╝  ╚═╝
-\033[0m
+BANNER = """\033[1;36m    ________  ______  ____
+   / ____/ / / / __ \\/  _/
+  / __/ / / / / /_/ // /
+ / /___/ /_/ / _, _// /
+/_____/\\____/_/ |_/___/\033[0m
 \033[1m  universal iso builder\033[0m
 \033[90m  any distro, from any distro\033[0m
 """