Add code infrastructure to validate file content (#14657)

* Implemented modular architecture for filestream security sanitization with an svg-html example

* 31440: Refactoring, applied to more entry points and removed test analyzer

* 31440 Added Unittests for FileStreamSecurityValidator

* PR fixes and better unittest mock names

---------

Co-authored-by: Sven Geusens <sge@umbraco.dk>

src/Umbraco.Core/EmbeddedResources/Lang/en.xml

@@ -341,6 +341,7 @@
     <key alias="createFolderFailed">Failed to create a folder under parent id %0%</key>
     <key alias="renameFolderFailed">Failed to rename the folder with id %0%</key>
     <key alias="dragAndDropYourFilesIntoTheArea">Drag and drop your file(s) into the area</key>
+    <key alias="fileSecurityValidationFailure">One or more file security validations have failed</key>
   </area>
   <area alias="member">
     <key alias="createNewMember">Create a new member</key>

src/Umbraco.Core/EmbeddedResources/Lang/en_us.xml

@@ -352,6 +352,7 @@
     <key alias="renameFolderFailed">Failed to rename the folder with id %0%</key>
     <key alias="dragAndDropYourFilesIntoTheArea">Drag and drop your file(s) into the area</key>
     <key alias="uploadNotAllowed">Upload is not allowed in this location.</key>
+    <key alias="fileSecurityValidationFailure">One or more file security validations have failed</key>
   </area>
   <area alias="member">
     <key alias="createNewMember">Create a new member</key>

src/Umbraco.Core/EmbeddedResources/Lang/nl.xml

@@ -340,6 +340,7 @@
     <key alias="renameFolderFailed">Kan de map met id %0% niet hernoemen</key>
     <key alias="dragAndDropYourFilesIntoTheArea">Sleep en zet je bestand(en) neer in dit gebied</key>
     <key alias="uploadNotAllowed">Upload is niet toegelaten in deze locatie.</key>
+    <key alias="fileSecurityValidationFailure">Een of meerdere veiligheid validaties zijn gefaald voor het bestand</key>
   </area>
   <area alias="member">
     <key alias="createNewMember">Maak nieuw lid aan</key>