## Issue Addressed
Addresses [#4401](https://github.com/sigp/lighthouse/issues/4401)
## Proposed Changes
Shift some constants into ```ChainSpec``` and remove the constant values from code space.
## Additional Info
I mostly used ```MainnetEthSpec::default_spec()``` for getting ```ChainSpec```. I wonder Did I make a mistake about that.
Co-authored-by: armaganyildirak <armaganyildirak@gmail.com>
Co-authored-by: Paul Hauner <paul@paulhauner.com>
Co-authored-by: Age Manning <Age@AgeManning.com>
Co-authored-by: Diva M <divma@protonmail.com>