Add website documentation

[dbulaja98]

Description:

• [x] Provide missing features documentation to the website
• [x] Address "TBD" in the current website documentation structure
• [x] Provide queries documentation
• [x] Provide requests documentation
• [x] Provide aggregations documentation
• [ ] Provide ElasticSort documentation
• [ ] Provide ElasticHighlights documentation
• [ ] Provide kNN request and query documentation