misc(share/p2p): reduce frequency of discovery retries

[ramin]

Fixes #3550 as suggested by guillaumemichel. In adjusting the "1 liner" realized there was some relatively funky stuff in tests where we set/reset a package level var for the interval, so moved both AdvertiserRetryTimeout and DiscoveryRetryTimeout to parameters and allowed customization where NewDiscovery is called. Also adjusted some of the intervals to be faster in tests so they execute within the test context Timeout and thus, hopefully will fix #3115

[Wondertan]

There is some wisdom behind the metaphor in ca67fef50f89af5cbbc1b4ebfebc40f733ddae92, but I am not getting it

[ramin]

There is some wisdom behind the metaphor in ca67fef, but I am not getting it

@Wondertan ah, I put it back how it was, so no unnecessary change :-)

[renaynay]

Let's hold off on this til we get conf from v0.14.1