.......... [ZBX-23987] rename the module
To bring Go code into adherence with the conventions described by the
module reference[1], the Go module is renamed to discard the
intermittent 'ap' directory and use the new, dedicated golang.zabbix.com
domain.
The module has accumulated more code, beyond just the scaffolding for
plugin development, and has thus been given the more generic 'sdk' name.
Imports and comments referring to packages in the modules have been
updated to reflect the change. The structure of the packages has been
left unchanged.
[1]: https://go.dev/ref/mod#module-path