Adds system testing workflow to github actions

[ManavalanG]

Pull request

• Adds a github actions workflow to perform system testing.
• It currently takes ~1.5-1.75hrs as it runs 4 system testing jobs in serial fashion.
• Refer Make system testing github actions run faster #74 to see discussions on optimization to make the workflow to run faster

Please fill in the checklist below and comment as needed.

• Was code modified? Briefly describe. Yes. System testing github actions workflow was added.
• Was documentation modified? Briefly describe. No.
• Is this a bug-fix? Briefly describe. No.
• Is this a feature addition? Briefly describe. Yes. See description above.
• Did you modify QuaC-Watch config file? If so, did you modify multiqc template
  configs/multiqc_config_template.jinja2 and script src/quac_watch/create_mutliqc_configs.py as necessary? No.
• Did you perform system-level testing manually as described in master readme doc? Did it pass completely? If not why? No, as this is now done using github actions
• Updated Changelog.md file with change logs in recommended format? Yes.

Anything else reviewer should know?

No.

[wilkb777]

LGTM

[ManavalanG]

Suddenly github actions for system testing keep failing, even though no changes have been made to concerning source code. It is unclear why this is happening :(

I got access to to larger runners but learnt later that they are not free to use. Relevant snippet:

* For larger runners, there is no additional cost for configurations that assign public static IP addresses to a larger runner. For more information on larger runners, see "Using larger runners."
* Entitlement minutes cannot be used for larger runners.
* The larger runners are not free for public repositories.
[4:56](https://cgds-uab.slack.com/archives/GTSEU473K/p1686866168293039)

I will get around to debugging the issue some day :(

[ManavalanG]

@wilkb777 Github actions workflow for system testing began failing despite no significant code changes, and the error had to do with lack of storage space. It is unclear why it worked before but started failing of late. I reran a workflow that had succeeded before, and it still errored out. After a series of debugging efforts (documented in #78), storage in the runners were freed first before running the github actions workflow. This resulted in resolving the issue.

So overall, I added a step in github actions workflow for system testing to free up disk storage space. Could you review the changes please? :)