fix: convert cf-kv and excalidraw-libraries from submodules to regular files

- Remove stale cloudflare-worker submodule entry from .gitmodules
- Remove .git dirs from cf-kv and excalidraw-libraries so Git tracks them as regular files
- Fixes 'No url found for submodule path cf-kv' CI error

excalidraw-libraries/stats/2021-02/2021-02-10.json

@@ -0,0 +1,30 @@
+{
+  "dbssticky-data-viz": 43,
+  "drwnio-drwnio": 82,
+  "drwnio-storytelling": 46,
+  "dwelle-hearts": 7,
+  "excacomp-mobile-kit": 17,
+  "excacomp-web-kit": 44,
+  "franky47-apple-devices-frames": 8,
+  "g-script-android": 10,
+  "g-script-charts": 14,
+  "g-script-forms": 65,
+  "g-script-medias": 11,
+  "h7y-dropdowns": 13,
+  "inwardmovement-information-architecture": 27,
+  "jakubpawlina-graphs": 65,
+  "lipis-polygons": 10,
+  "lipis-stars": 1,
+  "maeddes-technology-logos": 36,
+  "marcottebear-raspberrypi-zero": 13,
+  "morgemoensch-gadgets": 11,
+  "newbyca-cryptocurrencies": 6,
+  "pclainchard-it-logos": 15,
+  "revolunet-raspberrypi3": 5,
+  "shinkim-desktop-resolutions": 2,
+  "shinkim-lean-canvas": 2,
+  "shinkim-presentation-templates": 25,
+  "spfr-lo-fi-wireframing-kit": 56,
+  "youritjang-software-architecture": 119,
+  "youritjang-stick-figures": 46
+}