Simplify IT main/combined/distant icons with composed icons (#658)

Application of
#657 for
simplifying the IT icons.

Related to #639

cc @MatCr90 this PR simplifies the icon setup for the IT
main/combined/distant signals.

(http://localhost:8000/#view=16.99/45.666447/11.936039&style=signals):
<img width="1624" height="699" alt="image"
src="https://github.com/user-attachments/assets/48a3e332-68df-4f73-a658-e08e47824f5a"
/>

(http://localhost:8000/#view=16.62/45.541332/11.539128&style=signals):
<img width="1752" height="839" alt="image"
src="https://github.com/user-attachments/assets/0cabc0ea-6044-4dd2-b39b-410da1583a48"
/>

(http://localhost:8000/#view=18.96/45.5404914/11.5740117&style=signals):
<img width="757" height="502" alt="image"
src="https://github.com/user-attachments/assets/e0e43b6e-71ab-4a4f-b4fa-e1916c223434"
/>



TODO: 
- [x] example icons for preset/taginfo

Author: hiddewie