In the repository view, add label to LFS files displaying that the file pointed by the blob is not present
Right now, when we browse the repository and see an LFS blob, we don't know if the file pointed by that blob is present or not. We should display a label when the file is not present and therefore, the absence of it will mean that the file is present.
There are several cases when the LFS file couldn't be present in our database. For example, in gitlab-ce#40401 we're fixing the bug where LFS are not imported. But if we browse the repository there is no visual sign of this. Also, if we want to make the importation asynchronous or one of the downloaded LFS files fail the user won't be able to distinguish if it is present or not.