Add company field for doc types like customer, Item, Item group ... etc...,

[saivineeth100]

Is your feature request related to a problem? Please describe.
there's a high chance that customer, Item are not shared with other companies and belonged to one company only

Describe the solution you'd like
Create a company field for those doc types

Describe alternatives you've considered
we can have company as optional field also like we have for bank account, if selected then it belongs to selected company else it belongs to all companies

Additional context
Say big company with multiple Horizontals using this ERP, then items, customers, suppliers and every master is different for each company
or a CA firm using ERPNext to manage their clients then also its same