[EAGLE-845][IMPROVEMENT] Using aggregation query in backend instead of calculating count in frontend.

[IMPROVEMENT] Using aggregation query in backend instead of calculating count in frontend.
- Using siteId as query argument.
- Using aggregation query in backend instead of calculating count in frontend.

Author: chitin <chitin1027@gmail.com>

Closes #782 from chitin/refactorquery.
6 files changed