Move database ownership to System

[daniel-thom]

1. Move control over the database to the System instead of TimeSeriesMetadataStore. This will allow us to use the database for supplemental attributes.
2. Use SQL query params for user variables.

[daniel-thom]

We should probably change the name of this. At serialization time, we store this file in a time series directory. So, it could be mildly confusing when supplemental attributes are added. We would have to add support for deserializing old systems. I'm voting that we delay this for now.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 85.32110% with 16 lines in your changes missing coverage. Please review.

Project coverage is 95.07%. Comparing base (7f1d821) to head (fa2bb13).
Report is 8 commits behind head on main.

Files with missing lines	Patch %	Lines
src/infrasys/time_series_metadata_store.py	77.46%	16 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #41      +/-   ##
==========================================
- Coverage   95.21%   95.07%   -0.15%     
==========================================
  Files          31       32       +1     
  Lines        2529     2556      +27     
==========================================
+ Hits         2408     2430      +22     
- Misses        121      126       +5     

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[pesap]

Looks good to me!