PNG icons to inline SVG icons

Find and replace `png` icons with `inline svg` icons where is possible:

- [ ] `.ic_bd_spatial` - bd_spatial.png
- [ ] `.ic_bd_ftext` - bd_ftext.png
- [ ] `.ic_b_nextpage` - b_nextpage.png
- [ ] `.selectallarrow` - arrow_ltr.png
- [ ] `.fulltext` - s_fulltext.png, s_partialtext.png