rpc: refactor lib folder (#4836)

Closes https://github.com/tendermint/tendermint/issues/3857

Moves `lib/` folder to `jsonrpc/`.

Renames:

**packages**

`rpc` package -> `jsonrpc` package
`rpcclient` package -> `client` package
`rpcserver` package -> `server` package

**structs and interfaces**

```
JSONRPCClient to Client
JSONRPCRequestBatch to RequestBatch
JSONRPCCaller to Caller
```

**functions**

```
StartHTTPServer to Serve
StartHTTPAndTLSServer to ServeTLS

rpc/jsonrpc/client: rename NewURIClient to NewURI

NewJSONRPCClient to New
NewJSONRPCClientWithHTTPClient to NewWithHTTPClient
NewWSClient to NewWS
```

**misc**

- unexpose `ResponseWriterWrapper`
- remove unused http_params.go

lite2/proxy/proxy.go

@@ -12,7 +12,7 @@ import (
 	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	lrpc "github.com/tendermint/tendermint/lite2/rpc"
 	ctypes "github.com/tendermint/tendermint/rpc/core/types"
-	rpcserver "github.com/tendermint/tendermint/rpc/lib/server"
+	rpcserver "github.com/tendermint/tendermint/rpc/jsonrpc/server"
 )
 
 // A Proxy defines parameters for running an HTTP server proxy.
@@ -36,7 +36,7 @@ func (p *Proxy) ListenAndServe() error {
 	}
 	p.Listener = listener
 
-	return rpcserver.StartHTTPServer(
+	return rpcserver.Serve(
 		listener,
 		mux,
 		p.Logger,
@@ -54,7 +54,7 @@ func (p *Proxy) ListenAndServeTLS(certFile, keyFile string) error {
 	}
 	p.Listener = listener
 
-	return rpcserver.StartHTTPAndTLSServer(
+	return rpcserver.ServeTLS(
 		listener,
 		mux,
 		certFile,

lite2/proxy/routes.go

@@ -4,8 +4,8 @@ import (
 	"github.com/tendermint/tendermint/libs/bytes"
 	lrpc "github.com/tendermint/tendermint/lite2/rpc"
 	ctypes "github.com/tendermint/tendermint/rpc/core/types"
-	rpcserver "github.com/tendermint/tendermint/rpc/lib/server"
-	rpctypes "github.com/tendermint/tendermint/rpc/lib/types"
+	rpcserver "github.com/tendermint/tendermint/rpc/jsonrpc/server"
+	rpctypes "github.com/tendermint/tendermint/rpc/jsonrpc/types"
 	"github.com/tendermint/tendermint/types"
 )