[SDK] Create missing endpoints - Go

[LanaAb]

Automations:

• [x] List all automations
• [x] Get an automation

• [x] Get the subscriber activity for an automation

  Batching:

• [x] Make multiple requests in a single call

Timezones:

• [x] Get all available timezones

Campaign languages:

• [x] Get a list of all campaign languages available

[robgordon89]

done