monorepo: migrate to pnpm

[gabrocheleau]

This PR migrates npm to pnpm, notably to address issues where npm packagel-lock is generate to be environment specific (e.g. Linux or Mac). Pnpm allows cross-platform lockfiles.

[codecov]

Codecov Report

❌ Patch coverage is 68.29268% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.90%. Comparing base (89bc05b) to head (382c0c4).

Additional details and impacted files

Flag	Coverage Δ
block	84.33% <100.00%> (ø)
blockchain	89.13% <66.66%> (-0.20%)	⬇️
common	97.52% <100.00%> (ø)
evm	?
mpt	89.70% <75.00%> (+0.31%)	⬆️
statemanager	68.99% <66.66%> (-0.07%)	⬇️
static	99.77% <ø> (ø)
tx	90.04% <ø> (ø)
util	88.73% <100.00%> (ø)
vm	55.31% <50.00%> (-0.01%)	⬇️

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🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.