Implement `secrets tar` command

[aryanjassal]

Specification

A simple tar protocol is being merged to aid in the implementation of the secrets cp and secrets mv. The ground work for tar implementation would have been completed. Thus, a command that leverages this archival of files can be added. Instead of parsing the archive at the client side, we can give the user the archive in its entirety. As the tar generator and parser pair has been validated against existing tar implementations, this command should work out of the box.

Additional context

• Related to Implement secrets cp command #249
• Related to Implement secrets mv command #248

Tasks

1. Implement a secrets tar command
2. Support adding secrets from multiple vaults and naming the resulting archive

[linear]

ENG-562