Explicitly set default permission settings when generating tmpFiles

[doulikecookiedough]

Currently when a temp file is generated for data to be written into (and checksums to be calculated), we are using the default settings which relies on the JVM/system settings. This can potentially cause hashstore objects to be only accessible by a specific user (or specific group, which we made not want to add users to).

Hashstore objects should be group-readable so that we can set-up proper access control to external services (ex. metadig).

To Do:

• Explicitly declare permission settings when generating temp files
• Example code to assist: https://github.com/NCEAS/metacat/blob/7fd6e53e89f88f0545c22181e354341beec63543/src/edu/ucsb/nceas/metacat/admin/SolrAdmin.java#L709

[artntek]

capturing our slack convo:

default file permissions should be rw- r-- --- or posix 640

If setting these permissions on the temp file, please verify that these permissions also get transferred to the final location after the mv. Thanks!

[doulikecookiedough]

This has been completed via Feature-108: Default Permissions on HashStore Objects