Fix: Milestone progress bar v2

[kwek20]

Description of change

Progressbar now shows up when we walk down latest milestone -> latest solid during syncing. Previously this only showed up when we were moving back up from latest solid -> latest. As this part is the easy part and takes the least time, i added this

We have set a constant deciding that going down the tangle takes 95x as logn as going up and checking solidity.

Edit: Whoeps pushed the rebase of https://github.com/iotaledger/iri/pull/1856

Type of change

• Enhancement (a non-breaking change which adds functionality)

How was this tested

• Ran on a empty db
• Ran on an old snapshot db
• Ran on a running in sync node

[GalRogozinski]

Currently while running this branch I don't see this working while walking down...

[GalRogozinski]

I just debugged... The content of the progress logger is simply not being changed... I guess it is not walking down enough to change the percentage...

Will keep on monitoring