Add Terraform States to Backup and Restore tasks

What does this MR do?

Reuses standard file upload storage to cover Terraform states backup

Adds a seed for generating terraform state files under each project

Manual testing (in local GDK env):

• Verfied seed addition via bin/rake db:seed_fu FILTER=terraform
• Verified seed addition is repeatable
• Created backup: bin/rake gitlab:backup:create
• Verified output shows up:

2021-06-05 23:48:54 +0530 -- Dumping terraform states ...
2021-06-05 23:48:54 +0530 -- done

• Verified backup tar contains terraform_states.tar.gz
• Verified terraform_states.tar.gz carries content
• Verified that these contents remain encrypted in the backup and unreadable without keys
• Destroyed all records: Terraform::State.destroy_all
• Deleted all files: rm -rf shared/terraform_state/*
• Performed restore: bin/rake gitlab:backup:restore
• Verified Terraform::State.all shows back older records
• Verified association of builds to some of these records
• Verified shared/terraform_state/ is repopulated
• Verified Terraform::StateVersion.each do |sv| pp sv.file.read end works and shows the seed-added data
• Verified skipping of terraform_states keyword works:

2021-06-06 00:11:33 +0530 -- Dumping terraform states ...
2021-06-06 00:11:33 +0530 -- [SKIPPED]

Verified with same workflow as above (backup, destroy, delete, then restore) that skipped backup variant does not contain terraform_state.tar.gz and does not show up those files after restore

Miscellany:

Adds a missing test for LFS backups Adds File operation fixes to neighboring tests

Related Omnibus change: omnibus-gitlab!5336 (merged)

Closes #331806 (closed)

Screenshots (strongly suggested)

When skipped:

When included:

When restoring (if not skipped):

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have self-reviewed this MR per code review guidelines.
• I have followed the style guides.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)