Support advanced syntax in SERP (#4009)

Task/Issue URL:
https://app.asana.com/0/414730916066338/1206153302008458/f

### Description
This PR adds support for advanced syntax in SERP

### Steps to test this PR

- [x] In the url bar type filetype:pdf, search should return different
pdfs files
- [x] In the url bar type inurl:cat, search should return urls which
contain the word cat
- [x] In the url bar type intitle:cat, search should return websites
which title contains the word cat
- [x] None of the above should throw an Unable to open this type of link
error in a toast

app/src/main/java/com/duckduckgo/app/browser/SpecialUrlDetector.kt

@@ -81,7 +81,7 @@ class SpecialUrlDetectorImpl(
             SMSTO_SCHEME -> buildSmsTo(uriString)
             HTTP_SCHEME, HTTPS_SCHEME, DATA_SCHEME -> processUrl(initiatingUrl, uriString)
             JAVASCRIPT_SCHEME, ABOUT_SCHEME, FILE_SCHEME, SITE_SCHEME -> UrlType.SearchQuery(uriString)
-            null -> UrlType.SearchQuery(uriString)
+            null, FILETYPE_SCHEME, IN_TITLE_SCHEME, IN_URL_SCHEME -> UrlType.SearchQuery(uriString)
             else -> checkForIntent(scheme, uriString)
         }
     }
@@ -216,6 +216,9 @@ class SpecialUrlDetectorImpl(
         private const val FILE_SCHEME = "file"
         private const val SITE_SCHEME = "site"
         private const val EXTRA_FALLBACK_URL = "browser_fallback_url"
+        private const val FILETYPE_SCHEME = "filetype"
+        private const val IN_TITLE_SCHEME = "intitle"
+        private const val IN_URL_SCHEME = "inurl"
         const val SMS_MAX_LENGTH = 400
         const val PHONE_MAX_LENGTH = 20
         const val EMAIL_MAX_LENGTH = 1000