FSD: Entity trainer

[Quiddlee]

📝 Describe the refactoring task

Part of the issue #346
Trainer entity refactor

📍 Code location

src/entities/trainer

✅ Definition of Done (DoD):

1. create trainer folder in src/entities.
2. move src/widgets/trainers/ui/trainers-card to src/entities/trainer/ui/trainer-card.
3. create trainer-card.module.scss file in src/entities/trainer/ui/trainer-card and move all related to trainer-card styles from trainer.scss
4. refactor trainers.scss file to modules.scss and trainers-card.module.scss as so:

• remove all parent selector & .card-content -> .card-content.
• change all possible values to variables if such exists.
• rename all classes to be generic e.g .nodejs-trainer 🙅‍♂️ -> .trainer 👌.
• and everything in your opinion that needs to be refactored

5. move Trainer type from src/widgets/trainers/trainers.types.ts to src/entities/trainer/types.ts
6. create index.ts file and re-export Trainer type and TrainerCard component
7. refactor TrainerCard component to utilize HTML5 tags
8. Write unit test for TrainerCard component

Example of completing all the steps you can find in src/entities/event/event-card