suprsync: Use sqlite write-ahead-log

[BrianJKoopman]

Description

This enables write-ahead logging (WAL) for the sqlite files that the pysmurf-monitor and suprsync agents use.

Motivation and Context

Based on SQLite WAL documentation this should help with concurrency issues between the pysmurf-monitor writing to and the suprsync agent reading from the database. In particular I'll highlight the following line:

WAL provides more concurrency as readers do not block writers and a writer does not block readers. Reading and writing can proceed concurrently.

The monitor and suprsync agents all reside on the same machine, so this should work fine in this instance.

How Has This Been Tested?

I've only just run the integration tests locally.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.