build: add imports for go generate tools (#24682)

This adds a tools.go file to import all command packages used for
go:generate. Doing so makes it possible to execute go-based code
generators using 'go run', locking in the tool version using go.mod.

Co-authored-by: Felix Lange <fjl@twurst.com>

eth/tracers/logger/logger.go

@@ -59,7 +59,7 @@ type Config struct {
 	Overrides *params.ChainConfig `json:"overrides,omitempty"`
 }
 
-//go:generate gencodec -type StructLog -field-override structLogMarshaling -out gen_structlog.go
+//go:generate go run github.com/fjl/gencodec -type StructLog -field-override structLogMarshaling -out gen_structlog.go
 
 // StructLog is emitted to the EVM each cycle and lists information about the current internal state
 // prior to the execution of the statement.