MM-31063: Change constants to use CamelCase (#16608)

* MM-31063: Change constants to use CamelCase

* store package

* change allcaps to camel case (#16615)

* New tools.mod

Co-authored-by: Ibrahim Serdar Acikgoz <serdaracikgoz86@gmail.com>

app/constants.go

@@ -3,6 +3,6 @@
 
 package app
 
-const MISSING_CHANNEL_MEMBER_ERROR = "app.channel.get_member.missing.app_error"
-const MISSING_ACCOUNT_ERROR = "app.user.missing_account.const"
-const MISSING_AUTH_ACCOUNT_ERROR = "app.user.get_by_auth.missing_account.app_error"
+const MissingChannelMemberError = "app.channel.get_member.missing.app_error"
+const MissingAccountError = "app.user.missing_account.const"
+const MissingAuthAccountError = "app.user.get_by_auth.missing_account.app_error"