too many terms for the same thing (memoryStore/tank/aggmetrics/ring buffer/...)

[Dieterbe]

these all describe the same thing:

• MemoryStore (in api server) (easily confused with store plugins)
• Tank (in exported metrics and a couple places in the docs) (not very descriptive, hard to search for)
• AggMetric(s): the name of the go implementation (reasonably clear what it may do (?) though not very clear what the implementation is)
• cicular buffer:, in-memory [ring]buffer: in some code go comments, config files and docs (very tied to the specific implementation, but doesn't really explain the "what" going into the ring buffer)

i want to reduce the amount of terms. perhaps to 1 for the general highlevel concept and another for the implementation. maybe simply "ringbuffer" for the concept (e.g. in docs, in metrics, in api server,...) and we keep AggMetric(s) for the classes that are being.. ringbuffered.. ?