As a new user, CSS and JS minification are enabled by default

[benorfaz]

Context The minification feature is mature and doesn't cause major issues. We can activate it by default so new users don't have to think about it.

Acceptance Criteria

• When I install WP Rocket and activate it, CSS and JS minification are enabled
• I toggle it on/off and save changes (as of today)
• When I update from a previous a version of WP Rocket, and minification was disabled, it is still disabled
• UX fix: Behavior is not consistent across features when toggling on-off. For minification, you must save settings before the exclusion box appears, which is not the case for others. Expectated behavior: when toggling on -> extra parameters (exclusion box) is immediately displayed.

Additional information Add any additional information that could help or be relevant.