refactor: ✨ (#418)

* refactor: ✨ move in one commit

Eveything in modules should probably be changed to `exported` defs.
The idea is to move everything first to keep proper history.

* refactor: 📝 add modules readme (wip)

* refactor: ✨ small move

* refactor: 📝 changed nestring, updated modules readme

* refactor: 📝 to document or not to document

* fix: 🐛 themes

replaced the template to use `main` and regenerated them
from lemnos themes.

* Revert "fix: 🐛 themes"

This reverts commit 4918d3633c8d2d81950a0ed0cfd9eb84241bc886.

* refactor: ✨ introduce sourced

- Created a source `root` in which sourcable demos are stored.
  Some might get converted to modules later on.
- Moved some files to bin too.

* fix: 🐛 fehbg.nu

* fix: 🐛 modules/after.nu

* moved some other stuff around

---------

Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>

sourced/progress_bar/progress_bar_no_back.nu

@@ -0,0 +1,16 @@
+let blocks = ["▏" "▎" "▍" "▌" "▋" "▊" "▉" "█"]
+let pb_size = 25
+ansi cursor_off
+1..<$pb_size | each { |cur_size|
+    0..7 | each { |tick|
+        let idx = ($tick mod 8)
+        let cur_block = ($blocks | get $idx)
+        print -n $"(ansi -e '1000D')($cur_block | fill -c $blocks.7 -w $cur_size -a r)"
+        sleep 20ms
+    }
+    print -n $"(ansi -e '1000D')"
+}
+print $"($blocks.7 | fill -c $blocks.7 -w $pb_size -a r)"
+'Done'
+ansi cursor_on
+