feat(shared, frontend, backend): organise shared exports dual format build

[kevin9foong]

Problem

Enable dual-format building for shared package.

Requirements:

• esm support for react, newer node modules
• cjs support for older node modules
• dual format build tool which can help automate a bunch of items (eg, creating the exports mapping to cjs, esm)
• build tool should able to be used for sdk also (to provide standardization)

Closes [insert issue #]

Solution

Suggesting the following structure:

• modules: each module eg, logic has its own barrel
• utils: omit the barrel file, since each util is independent and not really related to each other, hence should have its own export
• types: support for barrel import and deep imports
• constants: support for barrel import and deep imports

To support the barrel for constants, we need to fix the name conflict with types in constants/fields/myinfo and constants/fields/basic, hence they have been renamed to avoid conflict.

Use tsdown to automate esm, cjs build and export resolution.

ci.yml dependency updates should theoretically speed up our ci.yml job completion by 1-2mins per run.

Breaking Changes

No - this PR is backwards compatible

[datadog-opengovsg]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

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[kevin9foong]

rationale: backend test does not need to wait for build, saving ~2mins in ci time

[kevin9foong]

note: these build files are not being used