NextCloud on CentOS

1. install and start the apache server

2. install php

3. set the php memory limit

4. enable php cache

5. install the database server

6. create the database

7. install redis

8. download the nextcloud, check the checksum and install it

9. set the SELinux contexts

10. define the apache virtual host for service

11. install the certboot

12. enable firewall

13. generate the certificate