rpc: make HTTP RPC timeouts configurable, raise defaults (#17240)

* rpc: Make HTTP server timeout values configurable

* rpc: Remove flags for setting HTTP Timeouts, configuring via .toml is sufficient.

* rpc: Replace separate constants with a single default struct.

* rpc: Update HTTP Server Read and Write Timeouts to 30s.

* rpc: Remove redundant NewDefaultHTTPTimeouts function.

* rpc: document HTTPTimeouts.

* rpc: sanitize timeout values for library use

node/defaults.go

@@ -24,6 +24,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/p2p/nat"
+	"github.com/ethereum/go-ethereum/rpc"
 )
 
 const (
@@ -39,6 +40,7 @@ var DefaultConfig = Config{
 	HTTPPort:         DefaultHTTPPort,
 	HTTPModules:      []string{"net", "web3"},
 	HTTPVirtualHosts: []string{"localhost"},
+	HTTPTimeouts:     rpc.DefaultHTTPTimeouts,
 	WSPort:           DefaultWSPort,
 	WSModules:        []string{"net", "web3"},
 	P2P: p2p.Config{