chore: Remove file description header

[acelyc111]

There is no functional changes in this patch, just remove the comments at the
head of file, the comments look like:

/*
 * Description:
 *     What is this file about?
 *
 * Revision history:
 *     xxxx-xx-xx, author, first version
 *     xxxx-xx-xx, author, fix bug about xxx
 */

The description which are meaningful has been moved closer to the class declaration
it descript.

This patch also updates some links, for example, from github.com/XiaoMi/pegasus/wiki
to pegasus.apache.org, github.com/XiaoMi/pegasus/issues to
github.com/apache/incubator-pegasus/issues.