Fix the tests and remove docker-compose

[simlmx]

• Use testcontainers to deal with the database
• Remove all references to sqlite (some of the schema being postgresql-specific)
• Pin some of the dependencies
• Add some dev dependencies
• Mark the tests requiring a live external API as such to make it easy to skip those when running locally
• The tests marked liveapi are still broken! See #54

[codecov-commenter]

Codecov Report

Merging #53 (dd4e862) into main (757cdf3) will decrease coverage by 48.46%. The diff coverage is 41.66%.

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@@             Coverage Diff             @@
##             main      #53       +/-   ##
===========================================
- Coverage   97.26%   48.81%   -48.46%     
===========================================
  Files           5        6        +1     
  Lines         256      295       +39     
===========================================
- Hits          249      144      -105     
- Misses          7      151      +144     

Impacted Files	Coverage Δ
pvconsumer/utils.py	76.08% <30.76%> (-17.86%)	:arrow_down:
pvconsumer/app.py	34.52% <41.66%> (-61.73%)	:arrow_down:
pvconsumer/save.py	45.45% <45.45%> (ø)
pvconsumer/__init__.py	100.00% <100.00%> (ø)
pvconsumer/solar_sheffield_passiv.py	24.56% <0.00%> (-75.44%)	:arrow_down:
pvconsumer/pv_systems.py	64.70% <0.00%> (-32.95%)	:arrow_down:

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