Refactor the code

[krashish8]

Refactor the code using Go linters, add style checks.
E.g.: https://goreportcard.com/report/github.com/Georepublic/pg_scheduleserv

[krashish8]

Ensuring code quality using golangci-lint from the GitHub actions. Based on the above link, golint looks a bit stricter, need to check its warnings.

Need to add linters to golangci-lint in the .golangci.yml file: https://golangci-lint.run/usage/linters/