Move spotdb into own project?

The "spotdb" (which is actually a caliper database) could be useful for other projects - could we move it into it's own module proper, and perhaps branded with caliper so it's clear that's what it's serving? Let me know what you think!

Start by locating the spotdb implementation and its current callers in the repository; the issue does not name files, tests, or entry points. Determine how the caliper database is coupled to SPOT and what moving it into a standalone, caliper-branded module would require. Done means the scope and module boundary are agreed, with any affected integration points identified.

Written by the indexing model from the issue text.