Build: Use caqti dynload at compile time for TPS measurement

Context

This allows to compile tps_measurement tools without postgresql installed on the machine lewering the barrier for devs. The dependency to postgresql caqti driver (and therefore postgresql) is postpone at runtime.

This requires opam-repository!349 (merged).

Manually testing the MR

Checklist

• N/A Document the interface of any function added or modified (see the coding guidelines)
• N/A Document any change to the user interface, including configuration parameters (see node configuration)
• N/A Provide automatic testing (see the testing guide).
• N/A For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR