feat: add variables. headers to graph\rest client

[valeryaosta]

1. Task: link

2. Screenshot:

3. Deploy: link

4. Done 01.09.2024 / deadline 16.09.2024

5. Score: 55

RESTfull client (completed prev dev logic)

• [x] Variables section that can shown or hidden, specified variables are included in the body. - 15 points
• [x] Headers section, value is provided in the url on header add/change. - 20 points GraphiQL route (completed prev dev logic)
• [x] Variables section that can shown or hidden, specified variables are included in the body. - 10 points
• [x] Header section that can be shown or hidden, value is provided in the url on header add/change. - 10 points