Create bundle.md (#341)

* Create bundle.md

A human readable bundle specification, specifically for the public good instances

Co-authored-by: Hayden B <hblauzvern@google.com>
Signed-off-by: Appu <appu@google.com>

* Update tlog entry info

Signed-off-by: Appu Goundan <appu@google.com>

---------

Signed-off-by: Appu <appu@google.com>
Signed-off-by: Appu Goundan <appu@google.com>
Co-authored-by: Hayden B <hblauzvern@google.com>