Fix "There are uncommitted changes" error messages when using mastodon-git with maston (core) 1.0.0-SNAPSHOT-31

[maarzt]

While using mastodon-git with the latest mastodon 1.0.0-SNAPSHOT-31, a user would often get error messages: that the repository is not clean "There are uncommitted changes. Please add a save point before pulling":

The problem also causes the unit tests to fail when using the latest mastodon core dependency.

In version 1.0.0-SNAPSHOT-31 the way Mastodon saves its projects/datasets has been changed, and mastodon-git needs to adapt. If mastodon saves into a folder now the entire old folder is removed. Which resulted in files project.xml_remote and other files that where created by mastodon-git in the mastodon.project folder are always be removed. Git notices these missing files and reports that as a "repository is not clean" error.

The problem is solved by no longer storing the files "project.xml_remote" etc. in the "mastodon.project/" folder. They are now stored in separate folder "mastodon.remote_data/".

With this changes user should again be able to do all operations mastodon-git provides.

TODOs

• [x] delete all test repositories that still use the old "project.xml_remote" files to avoid confusing users
• [x] rename "mastodon.remote" to "mastodon.initial_state"
• [x] cut a release

[maarzt]

We did a successful functional test yesterday. And the error message "FileNotFoundException" were due to the usage of a outdated matodon-git data repository. This change is backwards compatible. But I think we don't need to be backwards compatible yet. I will delete all outdated repositories. And merge this PR.