feat: add header and comet info service (#15850)

Co-authored-by: Aaron Craelius <aaron@regen.network>

core/header/doc.go

@@ -0,0 +1,7 @@
+/*
+Package header defines a generalized Header type that all consensus & networking layers must provide.
+
+If modules need access to the current block header information, like height, hash, time, or chain ID
+they should use the Header Service interface.
+*/
+package header

core/header/service.go

@@ -0,0 +1,19 @@
+package header
+
+import (
+	"context"
+	"time"
+)
+
+// Service defines the interface in which you can get header information
+type Service interface {
+	GetHeaderInfo(context.Context) Info
+}
+
+// Info defines a struct that contains information about the header
+type Info struct {
+	Height  int64     // Height returns the height of the block
+	Hash    []byte    // Hash returns the hash of the block header
+	Time    time.Time // Time returns the time of the block
+	ChainID string    // ChainId returns the chain ID of the block
+}