Add linters and fix lint issues

.golangci.yml

@@ -7,30 +7,43 @@ linters-settings:
 linters:
   disable-all: true
   enable:
+    - asciicheck
     - bodyclose
     - deadcode
     - dogsled
     - dupl
     - errcheck
+    - exhaustive
+    - exportloopref
+    - gci
     - gochecknoglobals
     - gochecknoinits
     - gocognit
     - goconst
     - gocritic
     - gocyclo
+    - godot
+    - goheader
     - goimports
     - golint
+    - gomnd
+    - goprintffuncname
     - gosec
     - gosimple
     - govet
     - ineffassign
     - interfacer
+    - lll
     - maligned
     - misspell
     - nakedret
+    - nestif
+    - noctx
+    - nolintlint
     - prealloc
     - rowserrcheck
     - scopelint
+    - sqlclosecheck
     - staticcheck
     - structcheck
     - typecheck