251 use jinja for job script rendering

[bschroeter]

Replaced in-source job script generation with Jinja templating.

For context - this simplifies the generation of job scripts (and indeed anything that interpolates into a template), meaning that we can remove the multiline string blocks, which are sensitive to whitespace, and abstract them into separate files.

This results in cleaner and more flexible code going forward and opens up opportunities to change the underlying templates at a moments notice.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (b65ddbb) 60.76% compared to head (623c0a3) 61.15%. Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #254 +/- ## ========================================== + Coverage 60.76% 61.15% +0.38% ========================================== Files 30 30 Lines 2238 2260 +22 ========================================== + Hits 1360 1382 +22 Misses 878 878 ```

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[bschroeter]

All tests pass btw.

PBS Job Id: 108301484.gadi-pbs
Job Name:   benchmark_cable_qsub.sh
Execution terminated
Exit_status=0
resources_used.cpupercent=371
resources_used.cput=00:05:21
resources_used.jobfs=0b
resources_used.mem=601672kb
resources_used.ncpus=18
resources_used.vmem=601672kb
resources_used.walltime=00:01:39