PLR: heat bed while waiting for user confirmation.

[vovodroid]

Implementation of @robherc idea to restore bed heating while waiting for user:

So maybe a safe compromise, which could address both concerns would be to have the printer immediately re-enable bed & chamber heaters after a power loss (to halt further warping and loss of buildplate adhesion); then wait for user-intervention before continuing the print (so an actual human gets a chance to ensure that resuming the print would still be safe/sane & that nobody has any fingers in the way of the spicy bits).

I also added option to raise bed temperature above set to improve or restore adhesion.

I turned auto heating off to keep current behavior, but probably it's worth to turn it on.