Add and expose settings for SD find debounce as config options

[tommyhaley]

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

[tommyhaley]

@GenivivSOMEIPmaintainer How to get attention from maintainer/reviewer?

[lutzbichler]

Could you please add some comment on why this is needed?

[tommyhaley]

It is not trivial to ensure that the SD Find messages associated with a given someip application is included in the 1st SD Find sent out by the vsomeip router and the 2nd SD message is typically sent out significantly later (by default debounce is 500 ms).

This change provides the possibility to debounce a configurable number of "initial SD Find" at a higher rate than default rate, which is important for vsomeip applications with requirements to get their SD Find sent out "early".

If the vsomeip application didn't manage to register (and request service) at the vsomeip router before the 1st SD Find debounce but shortly after, then the 2nd SD Find debounce (which will include the requested service) will be sent out only e.g. 100 ms later than the 1st SD Find debounce (and 400 ms earlier compared with if default debounce rate was used).

See examples below where where I.W. denote "Random Initial Wait"

Default debounce (timer 500 ms)
|I.W. |..................................................|..................................................|..................................................|...

Three initial debounces (timer 100 ms)
|I.W. |..........|..........|..........|..................................................|..................................................|..................................................|...