Move H1 heading to top of README
Move the main heading of the README to the first line of the file.
This conforms with markdownlint defaults.
Re-run doctoc to update table of contents.
+# Submariner
+
<!-- START doctoc generated TOC please keep comment here to allow auto update -->
<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
-- [Submariner](#submariner)
- [Architecture](#architecture)
- [Network Path](#network-path)
- [Prerequisites](#prerequisites)
<!-- END doctoc generated TOC please keep comment here to allow auto update -->
-# Submariner
<!-- markdownlint-disable line-length -->
[![End to End Tests](https://github.com/submariner-io/submariner/workflows/End%20to%20End%20Tests/badge.svg)](https://github.com/submariner-io/submariner/actions?query=workflow%3A%22End+to+End+Tests%22+branch%3Amaster)
[![Unit Tests](https://github.com/submariner-io/submariner/workflows/Unit%20Tests/badge.svg)](https://github.com/submariner-io/submariner/actions?query=workflow%3A%22Unit+Tests%22)
