Improve setup checks API

[come-nc]

Summary

The idea here is to avoid using the name as a key in the array as the name of setup checks is translated.
Before:

{
"dav": {
"Checking for DAV system address book": {
"severity": "success",
"description": "No outstanding DAV system address book sync.",
"linkToDoc": null
}
},
"security": {
"Checking for old user imported certificate": {
"severity": "success",
"description": null,
"linkToDoc": null
},
"Code integrity": {
"severity": "info",
"description": "Integrity checker has been disabled. Integrity cannot be verified.",
"linkToDoc": null
},

After:

{
"dav": {
"OCA\\DAV\\SetupChecks\\NeedsSystemAddressBookSync": {
"name": "Checking for DAV system address book",
"severity": "success",
"description": "No outstanding DAV system address book sync.",
"linkToDoc": null
}
},
"security": {
"OCA\\Settings\\SetupChecks\\CheckUserCertificates": {
"name": "Checking for old user imported certificate",
"severity": "success",
"description": null,
"linkToDoc": null
},
"OCA\\Settings\\SetupChecks\\CodeIntegrity": {
"name": "Code integrity",
"severity": "info",
"description": "Integrity checker has been disabled. Integrity cannot be verified.",
"linkToDoc": null
},

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)