* make min_wtema difficulty chain type dependent
* fix bad graph weights for automated and user testing
* only mainnet can get wtema difficulty unstuck at 59s blocks
* Introduce GLOBAL_CHAIN_TYPE and make CHAIN_TYPE thread_local.
This makes testing more explicit and significantly more robust.
* set_local_chain_type() in tests
* cleanup - weird
* get pool tests working with explicit local chain_type config
* core tests working with explicit local chain_type
* p2p tests working with explicit local chain_type
* store tests working
* cleanup, feedback