Add spent addresses export test

[DyrellC]

Description

Adds a regression test for exporting and importing spentAddresses.txt files using the export-spent and merge-spent iri-extension tools. The tests export the spent addresses of one node into a file and checks to ensure that they have been exported correctly. It then imports the same addresses into an empty node and checks that the addresses were added as spent addresses.

**Note: This test currently only tests with one spent address db to test and is an incomplete PR until further notice. It should not be merged until the additional test has been added, but needs to be tested in the build pipeline to ensure it is working correctly.

Fixes #1468

Type of change

• Enhancement (a non-breaking change which adds functionality)

How Has This Been Tested?

• Locally tested prior to change in file location
• Testing on buildkite pipeline to ensure pod file locations are correct **

Checklist:

• My code follows the style guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas