[CHANGE] Switched to `django-solo` to provide the Singleton model

[ppfeufer]

Description

Changed

• Switch to django-solo to provide the singleton for the settings model, instead of the custom implementation

Type of change

• [ ] 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 not to work as expected)

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my code
• [x] I have commented on my code, particularly in hard-to-understand areas
• [x] I have checked my code and corrected any misspellings

[codecov[bot]]

Codecov Report

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

Project coverage is 52.08%. Comparing base (f7a96e6) to head (436e781). Report is 2 commits behind head on master.

Additional details and impacted files

[](https://app.codecov.io/gh/ppfeufer/aa-srp/pull/221?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Peter+Pfeufer) ```diff @@ Coverage Diff @@ ## master #221 +/- ## ========================================== - Coverage 52.26% 52.08% -0.17% ========================================== Files 21 21 Lines 1242 1227 -15 Branches 211 210 -1 ========================================== - Hits 649 639 -10 + Misses 585 581 -4 + Partials 8 7 -1 ``` | [Files with missing lines](https://app.codecov.io/gh/ppfeufer/aa-srp/pull/221?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Peter+Pfeufer) | Coverage Δ | | |---|---|---| | [aasrp/admin.py](https://app.codecov.io/gh/ppfeufer/aa-srp/pull/221?src=pr&el=tree&filepath=aasrp%2Fadmin.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Peter+Pfeufer#diff-YWFzcnAvYWRtaW4ucHk=) | `50.54% <100.00%> (-0.46%)` | :arrow_down: | | [aasrp/models.py](https://app.codecov.io/gh/ppfeufer/aa-srp/pull/221?src=pr&el=tree&filepath=aasrp%2Fmodels.py&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Peter+Pfeufer#diff-YWFzcnAvbW9kZWxzLnB5) | `95.81% <100.00%> (+1.11%)` | :arrow_up: | ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/ppfeufer/aa-srp/pull/221?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Peter+Pfeufer). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Peter+Pfeufer) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/ppfeufer/aa-srp/pull/221?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Peter+Pfeufer). Last update [f7a96e6...436e781](https://app.codecov.io/gh/ppfeufer/aa-srp/pull/221?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Peter+Pfeufer). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Peter+Pfeufer).