feat: add pallets/events endpoint (#1204)

* add events pallet events endpoint
add unit tests
add e2e test

* update docs for pallet events endpoint

* add statemint e2e tests for pallet events endpoint

* update events references

* remove duplicate IPalletEventsParam reference

* lint

* add events check to getPalletMetadataType
add unhappy path check to fetchEventItem unit tests

* merge master

* update abstratpalletservice types
refactored events items assignment

* update error message to reflect more accurately when the pallet metadata has no items to query of a specific field type

* debug historicApi pallets

* update check for isValidPalletName to use the pallet meta data instead of the historicApi

* update error log for when a pallet id is not recognized

* yarn lint