Remove Epoch 0

[bengtlofgren]

As @juped mentioned, we should not have an epoch 0. It makes sense for the Namada blockchain to start at Epoch 1.

[sug0]

not really a bug I'd say, and more trouble than it's worth getting into. a lot of logic relies on the fact epochs start counting from 0. who knows what would break from meddling with that logic

[tzemanovic]

Not a fan of indexing from 1 but on the other hand it would be more consistent appearance with block height. The thing with the block height is that we have to start from 1 because tendermint treats height 0 as a special value, it doesn't know or care about epochs

[juped]

absolutely a protocol bug, some things including masp use nonexistent epoch 0 as a sentinel, genesis versions of per-epoch data that exist before any blocks are produced must go somewhere, etc. same situation as height 0

[tzemanovic]

There is no strong motivation to go with this change. Initializing state at epoch 0 is fine as init_chain doesn't commit anything and the first block simply begins at epoch 0 without any of the epoch increment logic that's applied after epoch 0