Embedd chainspecs as resources.

[LukaszRozmej]

Chainspecs should be embedded in binaries. And allow being referenced by path (as now) and by name (embedded) from config files

[dceleda]

@LukaszRozmej could say more about the rationale? It's always good to add them to an issue.

[LukaszRozmej]

So people won't use outdated chainspec when upgrading binaries for hardforks

[tkstanczak]

has some disadvantages too, does not allow for any quick fixes and adjustment or config fixes without release

[smartprogrammer93]

@tkstanczak you can still specify a chainspec from a file if needed. Please check the associated PR.