PARQUET-2478: Update README with link to parquet website

[alamb]

You can see the rendered version of this README here:

https://github.com/alamb/parquet-mr/tree/alamb/website_link?tab=readme-ov-file#parquet-mr-

Jira

• [x] My PR addresses the following Parquet Jira issues and references them in the PR title. For example, "PARQUET-1234: My Parquet PR"
  • https://issues.apache.org/jira/browse/PARQUET-XXX
  • In case you are adding a dependency, check if the license complies with the ASF 3rd Party License Policy.

Tests

• [x] My PR adds the following unit tests OR does not need testing for this extremely good reason: No code is changed

Commits

There is a single commit with a self explanatory description

• [x] My commits all reference Jira issues in their subject lines. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Style

There are no code changes

• [x] My contribution adheres to the code style guidelines and Spotless passes.
  • To apply the necessary changes, run mvn spotless:apply -Pvector-plugins

Documentation

This PR has no java code changes, only markdown

• [x] In case of new functionality, my PR adds documentation that describes how to use it.
  • All the public functions and the classes in the PR contain Javadoc that explain what it does