Clone drupal9 to pi4

1. The source directory chiao@pi4:~/public_html/drupal9 does not need to be changed.
   
2. Export drupal database from kpci7 as sql source file from here.
3. Save the sql as drupal_kpci72004_20211108.sql
4. sed 's/utf8mb4_0900_ai_ci/utf8mb4_unicode_ci/g' drupal_kpci72004_20211108.sql > drupal_kpci72004_20211108_update.sql
5. Import drupal_kpci72004_20211108_update.sql to pi4 MySQL database (by phpmyadmin):
   1. Clone drupal database in pi4 as drupal_pi4_20211108
   2. Drop drupal database in pi4
   3. Import drupal_kpci72004_20211108_update.sql
      
6.  Done.