Refactor version detection / filling for Syndesis version in the new project wizard

At the moment we use the provided versions from the online properties file.

Idea:
If we detect a "-SNAPSHOT" version in the properties file we will check if that version is available from a repository. If yes, then we will fill it to the combo box allowing it to be used. If not, then we will search for the latest artifact with that version from available repositories and fill that version into the combo box. If there is no version available at all with that version we will not fill it in the combo box and just ignore the entry. (see OnlineArtifactVersionSearcher)

Background:
While in development there will be no -SNAPSHOT available except you built syndesis locally. Thats why we check if the version is available as this will allow devs working on syndesis locally to test their changes directly. If you don't have those artifacts available locally then we are still in development phase for that version. We will have productized bits available from an EA repo but those won't be named -SNAPSHOT. Thats why we then search for the latest available artifact version and fill that instead into the combo box. This will also help us to have a working CI build all the time.
Once the Syndesis version got released we will replace the -SNAPSHOT entry in the properties file with the released version. When that happens the whole lookup logic will be skipped and the release version will be used instead.

Work Items:

• put the -SNAPSHOT version in the properties file
• extend the loading logic for that property file to do the proposed modifications
• also change the fallback if loading of the properties file fails for some reasons
• only fill non -SNAPSHOT versions into the combo in the wizard