Allow Using Boot Pool for TrueSearch Index

Problem/Justification

For people (like myself) that dont have a SSD pool, but do have a SSD for the boot pool, it would be nice to use it for the TrueSearch/Spotlight search index. I understand the logic behind not wanting to partition the boot pool to store data, but the search index data doesnt really matter at all since it can be regenerated at any time. Would be fantastic to be able to utilize the unused space on that disk and get the advantage of a fast search without needing to add an entire SSD pool.

Impact
This should not affect any user who does not explicitly set it up. The benefits would be getting the search speed increases of using SSDs, without needing to add a new pool. Would allow you to get more out of the large boot disk that most people have, but don’t use.

User Story
(Please give a short description on how you envision some user taking advantage of this feature, what are the steps a user will follow to accomplish it)

As a user I want to be able to select the boot partition when selecting the pool to use for TrueSearch.