wotstore update of trust rules

[cheme]

For now trust are only updated when adding peersign, and is therefore all manual, and it should stay that way at a kvstore level.

A first thing was (see example wotaccess in fs) to add peer discovery in accept rules of peer. Yet this is only ok when using trusted peers, and function/rules such as accept should be plugged in code to allow customazible trust of Keyval update (either discovery or publication)!!!

• when a trust is updated (for peer or keyval), it is currently only updated locally in the store but no sign of the updated value is calculated : this seems unreasonable to sign at every update (a new peersign may change all trusts). On the other hand an up to date sign should be needed when the trust is queried from outside :
  • sign from ourself should be added to promoted sign replies (only for wotstore - at a store level here)
• Keyval rules similar to accept must be added, this is very important to validate keyval received (so we can look for other trusted val there to get more inf). Please not that it as nothing to do checking of signing of trustedkeyval done when adding a trusted value in trustedstore), it is applicative code in rules. Discovery may be pluged here.

At this point trust refresh is done on reception of value, but nothing is done for existing values : the store update them when receiving other values (done in wotstore envery new peersign update existing trust).
What is missing is more trust publishing : do some sendval on the network regularly. This meet question of propagating KeyVal in network out of queries and is not purely trust rules issue.