Miscellaneous enhancements for 2023-W44

[khaeru]

• Improve ExoDataSource:
  • "name" attribute used for keys.
  • "extra_dims" attribute if returned data will have more dimensions than (n, y).
  • transform() method that can be overloaded by subclasses.
• Improve iamc_like_data_for_query():
  • Allow selecting a specific archive_member.
  • Configure handling of region codes that are not ISO 3166 country names.
• Add .project.advance, an exogenous data source for the ADVANCE project database, fuzzed data for testing, tests. Supersedes .tools.advance.
• Improve and combine mix-models ssp make-test-data CLI command and .tools.advance._fuzz_data() to mix-models testing fuzz-private-data, usable for SSP, ADVANCE, and other data sources.
• Add .tools.iamc.describe() to generate code lists given data in the IAMC structure.
• Add .workflow.make_click_command() to automatically generate a CLI for any Workflow.
• Add fetch CLI command; supersedes message_data.tools.download and the narrower message_ix_models.snapshot CLI.
• Remove message_ix_models/data/water/ files from packaging; this shrinks the package from >20 MB to <5 MB.
  • Provide an archive of these files + code + CLI to allow downloading them.
• Rename report.computations → report.operator (cf. Change term ‘computations’? khaeru/genno#34, Add an Operator class khaeru/genno#98, Rename 'report', 'util' + miscellaneous clean-ups ixmp#500).
• Improve test coverage in .report.

How to review

Read the diff and note that the CI checks all pass.

PR checklist

• Continuous integration checks all ✅
• Add or expand tests; coverage checks both ✅
• Add, expand, or update documentation.
• Update doc/whatsnew.

[codecov]

Codecov Report

Merging #137 (5b52a7b) into main (294ac47) will increase coverage by 0.9%.
The diff coverage is 92.6%.

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #137     +/-   ##
=======================================
+ Coverage   73.3%   74.3%   +0.9%     
=======================================
  Files         82      89      +7     
  Lines       5663    5942    +279     
=======================================
+ Hits        4155    4416    +261     
- Misses      1508    1526     +18     

Files	Coverage Δ
message_ix_models/cli.py	100.0% <ø> (ø)
message_ix_models/model/bare.py	100.0% <100.0%> (ø)
message_ix_models/model/build.py	100.0% <100.0%> (ø)
message_ix_models/model/cli.py	100.0% <100.0%> (ø)
message_ix_models/model/emissions.py	98.0% <100.0%> (ø)
message_ix_models/model/macro.py	100.0% <100.0%> (ø)
message_ix_models/model/snapshot.py	100.0% <100.0%> (ø)
message_ix_models/model/structure.py	100.0% <100.0%> (ø)
message_ix_models/model/water/reporting.py	4.8% <100.0%> (ø)
message_ix_models/project/advance/data.py	100.0% <100.0%> (ø)
... and 31 more