FW: more efficient dataformat for buffered sensors for higher throughput

[mkuettner97]

we need a universal format for buffered sensors for less overhead. For all sensors that read values from a buffer we have a big unnecessary overhead and these sensors usually operate at a high sample rate which creates problems for both sd card and ble. This is currently an issue for the PPG sensor at high sample rates.

• Support bigger data frames for sd writes.
• push big frames to sensor bus and split for BLE transmission
  --> find a policy for more equal transmission of across sensors that does not prevent sensors from suppressing others
• adjust this for the decoding script

[mkuettner97]

Suggestion: All sensor values within a frame must have the same time difference, otherwise we do not support this format. We only support this for fast sample rates because otherwise we don't have any issues with the sample rate. Therefore, uint16_t is enough for time diff in micros.
Parsing: size = sizeof(delta time) + n * size_per_sample --> from sensor parse scheme