cli and RemoteManager: add user messages

- add management of errors of remote commands
- add user messages to the console for vle cli
RemoteManager: fix actionUpdate results

- the PackageIdUpdate operator is fixed
- the results of the update command is filled with packages with newer versions
- the error is managed by filling mHasError and mMessageError
RemoteManager: fix install

- the more recent version of the package is installed
- one checks if the package is already installed
RemoteManager: update show commands

- add a localshow command, the show command now only show packages from remotes
- the argument of these command is the name of packages
- update help pages