Don’t check existence of files when saving project

[matthias-ronge]

If changes to the project settings are saved, you can see in the log file that all metadata files are checked for their existence. This makes saving the project very slow if the project has many processes.

Goal: When saving a project, metadata files should not be searched for

[matthias-ronge]

@andre-hohmann wrote in #4059:

Saving of changes in the project and redirection to the list takes a long time. The green button "You will be redirected after successful save." is shown, but only after a while, you get redirected to the project list. In that time, it is possible to work on some other elements like Folder use.
In that time, a ring is circling besides the mouse cursor, indicating, that something is working in the background.

[matthias-ronge]

From the log, MetsService is reading the metadata files of all processes of the project. This takes minutes on a productive system when you change project settings and shouldn’t be necessary here.