Migrate from npm to pnpm

[lemistt]

As a developer I want to replace npm in both the main project and the webcomponents with pnpm in order to increase build speed and disk efficiency locally and on the pipeline.
If it's easy, it might be worth it to implement workspaces? Should be investigated.

• AC1: The pipeline and build scripts work the same as they did before.

DoD

• Story is tested against acceptance criteria
• Unit test should be passed
• Integration test is done ( if applicable)
• Non-functional requirements are met
• Story ok-ed by Product Owner
• Peer Code Review performed
• Any configuration or build changes documented

Tasks:

• Migrate locally from npm to pnpm
• Adjust the Github Actions

[pestadieu]

See the branch: 79-migrate-to-pnpm

The whole migration has been done. The only remaining thing is that the Cypress test is not passing in Github action (See here: https://github.com/AkrosAG/Akros-Marketplace/actions/runs/3195750399/jobs/5216830309).
The test is passing localy but not in Github Actions.