Reduce costs and estimation for delete modules

[peterpeterparker]

We can probably reduce costs of deleting canisters by first setting the freezing threshold to zero.

Then there should be a liquid cycles endpoints that provides an estimatation of how many cycles to keep to delete a canisters. Note that Vivienne mentionned that 0.2 T Cycles should generally be ok according the SDK team experience, assuming the threshold is set as mentionned above.