Update links for software homepages

Avoid redirects.

This is the current situation:
* MySQL: http://www.mysql.com/ redirects to https://www.mysql.com/
* MariaDB: http://mariadb.org/ redirects to https://mariadb.org/
* Percona: https://www.percona.com/ redirects to http://www.percona.com/
* PostgreSQL: https://www.postgresql.org/ redirects to http://www.postgresql.org/
* Oracle: https://www.oracle.com/ redirects to http://www.oracle.com/
* SQLite: http://www.sqlite.org/ redirects to https://www.sqlite.org/
* Microsoft: Supports http://www.microsoft.com/ and https://www.microsoft.com/
  and http://microsoft.com/ and https://microsoft.com/ redirects to https://www.microsoft.com/
* PHP: http://www.php.net/ redirects to http://php.net/
  and https://www.php.net/ redirects to https://php.net/

Change-Id: I3da95a22386cc5e479ac1365a6680bf54bdcd81a
Merge "Update links for software homepages"