refactors agent_cisco_meraki

[thl-cmk]

This is the first step towards the improving of the agent. For now there are no changes visible from the outside. This moves all API requests to a class hirachie based in the DataCache class. The API cache is not yet active.

Nexts steps:

• streamlining usage of "id" versus "id_"
• change the logic from include sections to exclude sections
• activate the API cache (with option to disable via wato)
• option to use the organisation id as host prefix