Store usage of attachment on license info generation

[lepokle]

Split from #580

The usage of a license file inside a license report should be stored to make this info available on the view attachments tab of a release. This way users see the most used license file and can rely on them if they are unsure which one to choose for license generation.

The usage should be updated on each license generation.

Adding:

• Files being used are protected from deletion.
• usage can be seen in mouse over in attachment view.

[mcjaeger]

requires test

[mcjaeger]

there are following things necessary:

• Remark field in the relations. see AttachmentUsage in https://github.com/sw360/sw360portal/blob/master/libraries/lib-datahandler/src/main/thrift/attachments.thrift
• UI for setting and unsetting usage, presumeably a new table as subsection in the project details, similar to clearing status, listing used attachments of a release and allowing to add or remove these.
• Setting the usage for CLI file automatically selects this for the Readme oss (license disclosure document) generation
• Setting the usage for source code bundle generation, selects this automatically for source code bundle generation.
• Used attachments (from releases) are locked against deletion. Only unused attachments can be deleted.

[mcjaeger]

Usage today:

• Setting the usage for CLI file automatically selects this for the Readme oss (license disclosure document) generation
• will be saved at license generation
• deletion be regenerating with other settings

Revisit this issue:

• UI for setting and unsetting usage, presumeably a new table as subsection in the project details,, listing used attachments of a release and allowing to add or remove these. Idea is to have the clearing report locked that is "logically connected" with the CLI file from license info
• UI view shall be hierarchical. not like clearing status (which is flat). By this way a user can see to which release an attachment belongs.
• This would lead to different "usage" types selectable: licenseInfoUsage, sourcePackageUsage, manualUsage.
• Usage shall be OR (opposed to XOR)
• On the UI overview, the usage shall be shown including all usage types.
• Setting the usage for source code bundle generation, selects this automatically for source code bundle generation.
• Used attachments (from releases) are locked against deletion. Only unused attachments can be deleted.
• Really not so important now: Attachment usage could also refer to component attachments, or project attachments itself. (very advanced)

drop so far:

• Remark field in the relations. see AttachmentUsage in https://github.com/sw360/sw360portal/blob/master/libraries/lib-datahandler/src/main/thrift/attachments.thrift