chore: replace underscore with lodash & remove core-js

[sakulstra]

underscore is quite dated and current standard seems to be lodash. By using fine grained import it wont affect the bundle as much.

implementing polyfills should be up to the client using the library not the library itself imo. Currently for most people this will lead to including core-js twice

[Dpalazue]

Thx

[christophercr]

@kvhnuke, @SteveMieskoski is it possible to merge this PR and release a new version? Currently this library is huge due to underscore and core-js