Duplicate definitions of schemas

[trishankatdatadog]

Description of issue or feature request:

There are duplicate definitions of schemas. For example, ROLE_SCHEMA is defined twice (here and here) in formats.py.

Current behavior:

Duplicated definitions.

Expected behavior:

Non-duplicated definitions.

[lukpueh]

Thanks, @trishankatdatadog!

Independently of solving the duplicate definition, I would appreciate your take on this schema-related issue secure-systems-lab/securesystemslib#183.

[adityasaky]

There was an effort to reduce confusions between roles and delegations in the reference implementation and clean up the schemas and roledb. Is #846 relevant here?

Edit: https://github.com/theupdateframework/tuf/pull/846/files#diff-342188447c824198a41061eb376e1898L103-L110

[lukpueh]

Thanks, @adityasaky! Looks like we (probably I) should soon start to finish the work, @awwad started in #660/#846.

[trishankatdatadog]

@lukpueh @adityasaky I agree, this needs a larger fix, but we should be able to quickly dedup this right now in TUF at least...