enh(Settings): Provide visual feedback to user when encryption app not installed.

[nfebe]

Under : Admin settings -> Security, The "Enable server-side encryption", toggle does not do anything unless the "encryption" app is present.

That make sense but it should provide visual feedback as to what is going on.

[solracsf]

I know this is not 100% directly related, but in some cases, (sys)admin shoudl be able to completely disable encryption and its activation with config param like 'encryption_available' => false. If this was set to false (default as true) encryption (and its modules) could not be installed (or, at very least, activated) trough the WebUI or the CLI.

In this case, a message should also inform the user that encryption modules can't be installed or enabled because of that flag set.

[nfebe]

I know this is not 100% directly related, but in some cases, (sys)admin shoudl be able to completely disable encryption and its activation with config param like 'encryption_available' => false. If this was set to false (default as true) encryption (and its modules) could not be installed (or, at very least, activated) trough the WebUI or the CLI.

In this case, a message should also inform the user that encryption modules can't be installed or enabled because of that flag set.

I have added a draft that moves towards something like that in separate pull request here : #49202

Handling that separately allows this to get resolved much faster.

@solracsf