Query almanac for validity domain

[ChristopherRabotin]

High level description

When one loads a BSP or BPC file, it's useful to know the overall span that it is valid for. At the moment, one can use the describe function, but that function requires manual parsing by a human. It would be helpful to have a way to return the epochs (min and max, regardless of number of segments) for which a given bsp is valid.

Requirements

What does the system need to do?

Test plans

How do we test that these requirements are fulfilled correctly? What are some edge cases we should be aware of when developing the test code?

Design

Document, discuss, and optionally upload design diagram into this section.

Algorithm demonstration

If this issue requires a change in an algorithm, it should be described here. This algorithm should be described thoroughly enough to be used as documentation, simply refer to an algorithm in the literature or in another piece of software that has been validated.