[Website] Adjust the footer content of the home page

[gosonzhang]

Description

The parent issue is: #4702

Adjust the footer content of the home page:

1. Remove the incubation and corresponding content;
2. The footer contains only 2 parts:
   a. apache authorization statement:
   “Copyright © 2020-2022 The Apache Software Foundation. Licensed under the Apache License, Version 2.0.”
   b. Project authorization statement:
   “The Apache Software Foundation Apache InLong, InLong, Apache, the Apache feather, and the Apache InLong project logo are either registered trademarks or trademarks of the Apache Software Foundation.”
   c. Content is centered

InLong Component

Other for not specified component

Are you willing to submit PR?

• Yes, I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct