Add static analyzer to discourage use of panic() (#15075)

* Implement static analysis to prevent panics

* Add nopanic to nogo

* Fix violations and add exclusions

Fix violations and add exclusions for all

* Changelog fragment

* Use pass.Report instead of pass.Reportf

* Remove strings.ToLower for checking init method name

* Add exclusion for herumi init

* Move api/client/beacon template function to init and its own file

* Fix nopanic testcase

beacon-chain/execution/block_cache.go

@@ -158,7 +158,7 @@ func trim(queue *cache.FIFO, maxSize uint64) {
 	for s := uint64(len(queue.ListKeys())); s > maxSize; s-- {
 		// #nosec G104 popProcessNoopFunc never returns an error
 		if _, err := queue.Pop(popProcessNoopFunc); err != nil { // This never returns an error, but we'll handle anyway for sanity.
-			panic(err)
+			panic(err) // lint:nopanic -- popProcessNoopFunc never returns an error.
 		}
 	}
 }

beacon-chain/execution/testing/mock_faulty_powchain.go

@@ -57,7 +57,7 @@ func (*FaultyExecutionChain) ChainStartEth1Data() *ethpb.Eth1Data {
 func (*FaultyExecutionChain) PreGenesisState() state.BeaconState {
 	s, err := state_native.InitializeFromProtoUnsafePhase0(&ethpb.BeaconState{})
 	if err != nil {
-		panic("could not initialize state")
+		panic("could not initialize state") // lint:nopanic -- test code.
 	}
 	return s
 }