Store the solution's 'requested by' and 'repo name' data in an spfs annotation for spk to use

[dcookspi]

This stores the Solution's 'requested by' data in the spfs runtime creates by spk commands, e.g. spk env.... The data is stored as an spfs annotation. spk commands run inside that runtime restore this data into the current environment's Solution object. This allows commands like spk info to access the correct 'requested by' information, instead of making do with the placeholder "required by current environment" text.

Originally, I looked at storing/restoring the full Solution data in the runtime, but the Solution objects contain a lot data. Some of the data isn't easily serialisable, most of it is already reconstructed from the current runtime and repos in current_env(), some of it applies for the initial solver run but doesn't inside a runtime, and the 'requested by' data that's part of PkgRequest objects that we need is marked to skip serialisation (which is correct because we don't want this included in other places where PkgRequest are written out). So this change only stores/restores the requested by data from the resolved packages in the original Solution in an annotation in spfs.

Example, before this change:

> spk env python -- spk info -v
Installed Packages:
  runtime/stdfs:{build,run}/=1.0.0/3I42H3S6  highest (required by current environment) 
  runtime/python:{build,run}/=3.9.7/XO645NLV highest (required by current environment) 
 Number of Packages: 2

And, after this change:

Installed Packages:
  runtime/stdfs:{build,run}/=1.0.0/3I42H3S6  highest (required by python/3.9.7/XO645NLV) 
  runtime/python:{build,run}/=3.9.7/XO645NLV highest (required by command line) 
 Number of Packages: 2

This requires the changes in #815 (spfs runtime extra data support)

Todo:

• Look at storing the original package sources so this information is available in the running environment
• Turn stored BTreeMap into a versionable struct to make extending it easier, consider using protocol buffer
• Update based on changes from spfs annotation data support #844

[codecov]

Codecov Report

Attention: Patch coverage is 25.66138% with 281 lines in your changes are missing coverage. Please review.

Project coverage is 53.87%. Comparing base (e8cf549) to head (40ca8fc).
Report is 421 commits behind head on main.

❗ Current head 40ca8fc differs from pull request most recent head dcf2146. Consider uploading reports for the commit dcf2146 to get more accurate results

Files	Patch %	Lines
crates/spfs-cli/main/src/cmd_run.rs	22.44%	76 Missing ⚠️
crates/spfs/src/runtime/storage.rs	56.75%	48 Missing ⚠️
crates/spfs/src/env.rs	0.00%	45 Missing ⚠️
crates/spk-cli/common/src/env.rs	0.00%	28 Missing ⚠️
crates/spfs/src/bootstrap.rs	0.00%	13 Missing ⚠️
crates/spk-solve/crates/solution/src/solution.rs	0.00%	13 Missing ⚠️
crates/spfs-cli/cmd-clean/src/cmd_clean.rs	0.00%	11 Missing ⚠️
crates/spfs-cli/cmd-monitor/src/cmd_monitor.rs	0.00%	9 Missing ⚠️
crates/spfs-cli/main/src/cmd_runtime_remove.rs	0.00%	5 Missing ⚠️
crates/spfs-cli/main/src/cmd_shell.rs	0.00%	5 Missing ⚠️
... and 9 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #837      +/-   ##
==========================================
+ Coverage   53.55%   53.87%   +0.32%     
==========================================
  Files         258      253       -5     
  Lines       20466    20218     -248     
==========================================
- Hits        10960    10893      -67     
+ Misses       9506     9325     -181     

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[dcookspi]

Added some todo items, following a discussion today.

[dcookspi]

Updated this for the external data to annotation name change.

[rydrman]

Overall seems good - couple of questions/thoughts for you