build!: Migrate to pub workspace

[provokateurin]

I'm not sure it will work right away, but let's see 🚀

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 28.61%. Comparing base (0390e23) to head (b1a31fb).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...ckages/nextcloud/lib/src/models/version_check.dart	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2704   +/-   ##
=======================================
  Coverage   28.61%   28.61%           
=======================================
  Files         374      374           
  Lines      144735   144735           
=======================================
  Hits        41417    41417           
  Misses     103318   103318           

Flag	Coverage Δ		*Carryforward flag
account_repository	98.47% <ø> (ø)
cookie_store	99.48% <ø> (ø)
dashboard_app	96.05% <ø> (ø)
dynamite	31.05% <ø> (ø)
dynamite_end_to_end_test	62.44% <ø> (ø)
dynamite_runtime	85.40% <ø> (ø)
interceptor_http_client	97.18% <ø> (ø)
neon_dashboard	96.05% <ø> (ø)		Carriedforward from 0390e23
neon_framework	59.23% <ø> (ø)
neon_http_client	92.38% <ø> (ø)
neon_notifications	100.00% <ø> (ø)		Carriedforward from 0390e23
neon_rich_text	100.00% <ø> (ø)
neon_storage	94.66% <ø> (ø)
neon_talk	99.45% <ø> (ø)		Carriedforward from 0390e23
nextcloud	24.22% <0.00%> (ø)
notifications_app	97.43% <ø> (ø)
notifications_push_repository	98.11% <ø> (ø)
sort_box	90.90% <ø> (ø)
talk_app	98.84% <ø> (ø)

*This pull request uses carry forward flags. Click here to find out more.

Files with missing lines	Coverage Δ
...ckages/nextcloud/lib/src/models/version_check.dart	64.70% <0.00%> (ø)

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[Leptopoda]

some initial feedback

[Leptopoda]

We should have it as a dev_dependency of the workspace package and just use a global analysis_options.yaml.

Every package may still alter the rule set but this would make our lints the default (also for newly added packages).

[provokateurin]

I didn't think about this, but yes it makes sense. How are we going to handle custom_lint though? We need to disable some of the rules for specific packages?
OTOH this brings up the point of removing custom_lint entirely, given that it mostly causes headaches and hasn't caught so many problems so far.

[provokateurin]

I put this into a separate issue as it's not really a blocker and we really need this PR to make everything simpler: #2925

[provokateurin]

For the tests with downgraded dependencies we probably need test: ^1.25.12: https://github.com/dart-lang/test/blob/master/pkgs/test/CHANGELOG.md#12512
Unfortunately we are currently stuck: #2680