Make Live Connect labels available for translation

The following labels are missing in Crowdin so we can translate them in French:
Home > Oauth Tokens tab

• Add a new googledrive token
  -> should be Add a new Google Drive token
• Service Name
• Service Login
• Access Token
• Refresh Token
• Creation Date
• Shared Token

File creation / edit forms

• Upload
• no file selected
  -> Should be No file selected

Note: oAuth Tokens tab should be renamed "Cloud Services". Buttons "Add a new googledrive token" should be "Connect to Google Drive", "Add a new GooglePlusTokenId" should be "Connect to Google Plus", "Connect to Dropbox", "Connect to Youtube"

In Admin Center, oAuth tab should be renamed "Cloud Services" too. (and we let oAuth on the sub tabs)