Add symlink handling options

[paulborgermans]

Currently symlinks are "followed" in the sense that these are treated as regular files. In some cases this is not desirable.

So mango_ingest should be expanded with:

• Have the option to ignore files that have a symlink component in their path and log those in the standard report
• Have the option to add information on the symlink related system metadata: src/destination of the symlinked path, mango_ingest upload folder, watched folder
• Ultimately have the option to upload stubs instead of ignoring which should carry the same 4 metadata items

[jefscheepers]

For each ignored symlink, the following info should be logged:

• file path/directory path
• Path where the symlink linked to

[ghuls]

Any update on this?

[paulborgermans]

The development branch now carries code to ignore symlinks