In this change a configurable initial debounce
interval for SD find as well as a configurable
number of initial debounces are introduced. This
implies that services requested in the initial
debounce phase will at most wait for an initial
debounce interval before being included in a SD
find debounce. After the initial debounce phase is
completed, all subsequent SD find debounces will
use the default debounce interval.

Added and exposed options:
* find_initial_debounce_reps
* find_initial_debounce_time

Exposed option:
* find_debounce_time

…ons"

Changed find_initial_debounce_reps from uint32_t to uint8_t
Simplified propsed logic change in service_discovery_impl

This commit should be squashed into previous.