update existing seek nodes and fix stuff

[wow-such-code]

• allow update of existing assays in SEEK (found via openBIS identifier) and their samples and attached assets
• inform user adding sample-types from openbis to SEEK, if they already exist and don't add them a second time. can be ignored via command line option
• do not create blobs for assets in SEEK, if the user only want to link to openBIS
• fix issue where SEEK authentication was asked of the user even if only openBIS commands were used
• fetch all patient ids that are connected to a selected dataset (instead of only the first one found)
• attempt to fix "NotFetchedException: Parents have not been fetched." problem by setting fetch options for more hierarchy levels
• move a number of mappings for openBIS==>SEEK to their own property files that can be edited by the user
• add parameters for project and study in SEEK
• add a number of parameters to the config file:
  ** seek_default_project
  ** seek_default_investigation
  ** seek_openbis_sample_title (name of the property to be created/used in SEEK sample types to reference the openBIS identifier)