Assert messages contains hardcoded values

[afalaleev]

Description
Text messages contains values which can be configured by leaders:

golos.contracts/golos.publication/golos.publication.cpp

Line 129 in 22523f1

eosio::check(headermssg.length() < config::max_length, "Title length is more than 256.");

golos.contracts/golos.publication/golos.publication.cpp

Line 127 in 22523f1

"Permlink length is empty or more than 256.");