Add option to choose the db tables prefix

[ghost]

Describe the bug

The installation doesn't let us to choose some important features : normaly, during the installation, we can choose the prefix to replace th "wp_" for the tables. It's a feature important to protect a little more against hack.

Currently, I have to do some steps in wp-config.php and database to have correct table's name :
Tuto to change prefix

Context

• Hardware: *VPS bought online / Old laptop or computer / Raspberry Pi at home
• YunoHost version: 4.3.6.2
• I have access to my server: Through SSH | through the webadmin | direct access via keyboard / screen | ...
• Are you in a special context or did you perform some particular tweaking on your YunoHost instance?: *no
• Using, or trying to install package version/branch: wordpress_ynh 5.8~ynh1

Steps to reproduce

• run a classic installation of wordpress.

Expected behavior

a box to write which prefix we want.