Dataset: add READMEs, organize scripts, update .gitignore

- Add README.md to all 16 dataset directories with script references
- Centralize generation scripts under scripts/ with full README
- Update .gitignore to cover all data directories, keep only metadata
- Remove redundant CCPD/.gitignore (parent covers same rules)
- Remove stale scripts/test/ (254MB pipeline residue)
- Fix label parser reference: scripts are authoritative source of truth

ccpd_combined_5k5k_spe/dataset.yaml

@@ -0,0 +1,10 @@
+# CCPD Combined Dataset (single class: license_plate)
+# CCPD2019 5k + CCPD2020 5k + CCPD_SPE all = 19000 images
+
+path: C:/Users/Kirl/Desktop/ICEv2/ICE_Dataset/ccpd_combined_5k5k_spe
+train: images/train
+val: images/val
+
+nc: 1
+names:
+  0: license_plate