Integrate skale-contracts library and remove manager and IMA ABIs

[dmytrotkk]

Using https://github.com/skalenetwork/skale-contracts library it's possible to get any contract address, ABI or contract object for IMA, manager and Allocator.

We need to integrate skale-contracts and use it in ima-agent.
In the new version skale-admin will no longer provide manager.json and ima.json, instead MANAGER_ALIAS and IMA_ALIAS will be passed.

We need to make according changes in the codebase of ima-agent and network-browser.