elf → lef, remove oauth nonsense

- use random.choice() instead of random.randrange() and checking for each number
- use proper `not` operator instead of `== False`
- use format strings instead of manually concatenating the components of the post
- use getpass.getpass() instead of input() for entering the user's password
- make the script executable using a shebang and chmod +x
- gitignore .lgfbot/
- use sets instead of lists for static containment checks

.gitignore

@@ -0,0 +1 @@
+config.json

config.example.json

@@ -0,0 +1,4 @@
+{
+	access_token: "...",
+	site: "https://freak.university",
+}

requirements.txt

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+mastodon.py ~= 1.8
+json5 ~= 0.9.11