feat: archive spool files

Description

feat: archive spool files

• files sent by send scripts are now archived into a log folder specified by LOG_DIR in send_lib.py
• the scripts now create a new file spool/ARCHIVE which is set based on backend configuration

DEPLOYMENT NOTE: LOG_DIR has to be configured and the directory has to exist on the engine machine

How to test

Set all necessary config properties/create folders and try service propagation through NGUI (relevant backend changes have to be deployed). The changes from this MR also have to be present in the devel machine engine directories (they are as of writing this). The send script has to be called (and ideally pass) as well. Be sure the send script uses generic_sender.py

Author's checklist

• I have followed the contribution guidelines
• This MR has been tested or does not change functionality
• I have added relevant merge request dependencies (if this MR has any)
• I have added the correct labels
• I have assigned reviewers (if any are relevant)
• I have edited the documentation (if the changes require it) or I have noted the need for the change if I do not have access to the documentation
• I have marked all introduced BREAKING CHANGES or necessary DEPLOYMENT NOTES in the commit message(s)

Reviewer's checklist

• This MR has been tested or does not change functionality
• This MR has correct commit message format

Other information

None

Related issues

Re STR-1230