Updated the admin interface

Mostly updated the admin interface, also some small other items.

- Added more diagnostic information to (hopefully) decrease issue
  reporting, or at least solve them quicker.
- Added an option to generate a support string which can be used to
  copy/paste on the forum or during the creation of an issue. It will
try to hide the sensitive information automatically.
- Changed the `Created At` and `Last Active` info to be in a column and
  able to sort them in the users overview.
- Some small layout changes.
- Updated javascript and css files to the latest versions available.
- Decreased the png file sizes using `oxipng`
- Updated target='_blank' links to have rel='noreferrer' to prevent
  javascript window.opener modifications.

src/api/core/mod.rs

@@ -172,7 +172,7 @@ fn hibp_breach(username: String) -> JsonResult {
             "Domain": "haveibeenpwned.com",
             "BreachDate": "2019-08-18T00:00:00Z",
             "AddedDate": "2019-08-18T00:00:00Z",
-            "Description": format!("Go to: <a href=\"https://haveibeenpwned.com/account/{account}\" target=\"_blank\" rel=\"noopener\">https://haveibeenpwned.com/account/{account}</a> for a manual check.<br/><br/>HaveIBeenPwned API key not set!<br/>Go to <a href=\"https://haveibeenpwned.com/API/Key\" target=\"_blank\" rel=\"noopener\">https://haveibeenpwned.com/API/Key</a> to purchase an API key from HaveIBeenPwned.<br/><br/>", account=username),
+            "Description": format!("Go to: <a href=\"https://haveibeenpwned.com/account/{account}\" target=\"_blank\" rel=\"noreferrer\">https://haveibeenpwned.com/account/{account}</a> for a manual check.<br/><br/>HaveIBeenPwned API key not set!<br/>Go to <a href=\"https://haveibeenpwned.com/API/Key\" target=\"_blank\" rel=\"noreferrer\">https://haveibeenpwned.com/API/Key</a> to purchase an API key from HaveIBeenPwned.<br/><br/>", account=username),
             "LogoPath": "bwrs_static/hibp.png",
             "PwnCount": 0,
             "DataClasses": [