faec689bed txmempool: Make entry time type-safe (std::chrono) (MarcoFalke)
faaa1f01da util: Add count_seconds time helper (MarcoFalke)
1111170f2f test: mempool entry time is persisted (MarcoFalke)
Pull request description:
This changes the type of the entry time of txs into the mempool from `int64_t` to `std::chrono::seconds`.
The benefits:
* Documents the type for developers
* Type violations result in compile errors
* After compilation, the two are equivalent (at no run time cost)
ACKs for top commit:
ajtowns:
utACK faec689bed
laanwj:
ACK faec689bed
Tree-SHA512: d958e058755d1a1d54cef536a8b30a11cc502b7df0d6ecf84a0ab1d38bc8105a67668a99cd5087a444f6de2421238111c5fca133cdf8e2e2273cb12cb6957845
ccaef6c28b