chore(Archive): convert to the module system

[grunweg]

Mostly mechanical migration, akin to what modulize.lean would do: make all imports public, and add @[expose] public section at the beginning of each file. (In a few cases of files without definitions, omit the expose attribute.)

Inspired by #36236; re-done by hand. All files omitted there are actually fine to hand-convert.

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[github-actions]

PR summary 8180fd74a7

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

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Declarations diff (regex)

No declarations were harmed in the making of this PR! 🐙

You can run this locally as follows

## from your `mathlib4` directory:
git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci

## summary with just the declaration names:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh in the mathlib-ci repository contains some details about this script.

Declarations diff (Lean)

✅ Lean-aware diff — post-build, computed from the Lean environment (commit 8180fd7).

• +0 new declarations
• −0 removed declarations

No declaration differences.

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No changes to strong technical debt.

Increase in weak tech debt: (relative, absolute) = (22.00, 0.00)

Current number	Change	Type (weak)
5041	22	exposed public sections

Current commit 8180fd74a7
Reference commit c026161a58

This script lives in the mathlib-ci repository. To run it locally, from your mathlib4 directory:

git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci
../mathlib-ci/scripts/reporting/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[felixpernegger]

Great PR; Did you check if some of these imports can be private? Since Archive is never really imported anyways; this shouldnt matter too much, but still nice to have

[grunweg]

Did you check if some of these imports can be private? Since Archive is never really imported anyways; this shouldnt matter too much, but still nice to have

I did not. Be my guest to do so in a follow-up PR. I don't think this needs to block merging this PR.