[feature request] we need to wrap `ios_webkit_debug_proxy` like AppiumDriverLocalService

Description

As java-client does not launch ios_webkit_debug_proxy when setting autoWebview=true desired capability or query context( e.g. driver.getContextHandles() ,driver.context(String), driver.getContext(), it would fail like below it testing on real iOS devices:

[MJSONWP] Encountered internal error running command: RequestError: Error: connect ECONNREFUSED 127.0.0.1:27753
at new RequestError (/usr/local/lib/node_modules/appium/node_modules/request-promise/lib/errors.js:11:15)
at Request.RP$callback as _callback
at self.callback (/usr/local/lib/node_modules/appium/node_modules/request-promise/node_modules/request/request.js:199:22)
at emitOne (events.js:90:13)
at Request.emit (events.js:182:7)
at Request.onRequestError (/usr/local/lib/node_modules/appium/node_modules/request-promise/node_modules/request/request.js:821:8)
at emitOne (events.js:90:13)
at ClientRequest.emit (events.js:182:7)
at Socket.socketErrorListener (_http_client.js:306:9)
at emitOne (events.js:90:13)
at Socket.emit (events.js:182:7)
at emitErrorNT (net.js:1249:8)
at _combinedTickCallback (internal/process/next_tick.js:74:11)
at process._tickCallback (internal/process/next_tick.js:98:9)

I think we could handle this by launching ios_webkit_debug_proxy as a service like AppiumDriverLocalService

Start by reading the existing AppiumDriverLocalService implementation and trace how local services are represented and managed. Determine where ios_webkit_debug_proxy should be launched for autoWebview and context queries on real iOS devices. Done means the proxy is managed by the Java client and those operations no longer fail with ECONNREFUSED.