[Feature] Add options for TOC: inline, popup, numbered (#95)

addressing this issue: https://codeberg.org/daudix/duckquill/issues/94

- You can now choose if you want to have and inline Table of Contents(TOC), a popup, or both!
- You can also choose between numbered and un-numbered TOC styles

note: please squash the commits
Reviewed-on: https://codeberg.org/daudix/duckquill/pulls/95
Co-authored-by: Alireza Alavi <alavialireza@protonmail.com>
Co-committed-by: Alireza Alavi <alavialireza@protonmail.com>

config.toml

@@ -206,3 +206,12 @@ show_qr = true
 #
 # Your GoatCounter username
 user = "duckquill"
+
+# Table of Contents (TOC) configs
+[extra.toc]
+# whether to render inline static TOC at the top of the articles or not
+inline = true
+# where to show the TOC as a pop-up button
+popup = true
+# Show numbered TOC
+numbered = true