feat: add vetkeys password manager example

[andreacerulli]

Move the password manager vetkeys examples from the dfinity/vetkeys repository into rust/vetkeys/. It includes frontend, Rust backend, and Motoko backend.

[fspreiss]

ICP Ninja links for this branch (just for reference):

• Motoko
• Rust

For Motoko, login and storing passwords seems to work.

For Rust, deployment fails with

Build failed: WARNING: Skipped audit step as there is no Cargo.lock file.
Building canister 'ic_vetkeys_encrypted_maps_canister'.
Executing: cargo build --target wasm32-unknown-unknown --release -p ic-vetkeys-encrypted-maps-canister --locked
    Updating crates.io index
error: the lock file /workdir/Cargo.lock needs to be updated but --locked was passed to prevent this
If you want to try to generate the lock file without accessing the network, remove the --locked flag and use --offline instead.
Building canister 'www'.
Executing 'cd frontend && npm i --include=dev && npm run build && cd - && rm -r dist > /dev/null 2>&1; mv frontend/dist ./'
npm warn deprecated @dfinity/principal@2.4.1: This package has been deprecated. Use @icp-sdk/core/principal instead. Migration guide: 
https://js.icp.build/core/latest/upgrading/v5
npm warn deprecated @dfinity/auth-client@2.4.1: This package has been deprecated. Its functionality is now part of `@icp-sdk/auth` (
https://js.icp.build/auth),
 under the `client` submodule.
npm warn deprecated @dfinity/identity@2.4.1: This package has been deprecated. Use @icp-sdk/core/identity instead. Migration guide: 
https://js.icp.build/core/latest/upgrading/v5
npm warn deprecated @dfinity/candid@2.4.1: This package has been deprecated. Use @icp-sdk/core/candid instead. Migration guide: 
https://js.icp.build/core/latest/upgrading/v5
npm warn deprecated @dfinity/agent@2.4.1: This package has been deprecated. Use @icp-sdk/core/agent instead. Migration guide: 
https://js.icp.build/core/latest/upgrading/v5
added 273 packages, and audited 274 packages in 30s
79 packages are looking for funding
  run `npm fund` for details
8 moderate severity vulnerabilities
To address all issues (including breaking changes), run:
  npm audit fix --force
Run `npm audit` for details.
npm notice
npm notice New major version of npm available! 10.8.2 -> 11.12.1
npm notice Changelog: 
https://github.com/npm/cli/releases/tag/v11.12.1
npm notice To update run: npm install -g npm@11.12.1
npm notice
> password-manager-frontend@0.1.0 build
> vite build
vite v5.4.21 building for production...
[plugin:typescript] [plugin typescript] @rollup/plugin-typescript TS5096: Option 'allowImportingTsExtensions' can only be used when one of 'noEmit', 'emitDeclarationOnly', or 'rewriteRelativeImportExtensions' is set.
./bundle.css doesn't exist at build time, it will remain unchanged to be resolved at runtime
transforming...
(node:165) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
(Use `node --trace-warnings ...` to show where the warning was created)
(node:165) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
🌼   daisyUI 4.12.24
├─ ✔︎ 2 themes added		
https://daisyui.com/docs/themes
╰─ ❤︎ Support daisyUI project:	
https://opencollective.com/daisyui
✓ 301 modules transformed.
rendering chunks...
computing gzip size...
dist/index.html                  0.48 kB │ gzip:   0.30 kB
dist/bundle.css                 67.48 kB │ gzip:  11.75 kB
dist/assets/index-DeAekZWc.js  738.02 kB │ gzip: 245.09 kB │ map: 2,944.52 kB
(!) Some chunks are larger than 500 kB after minification. Consider:
- Using dynamic import() to code-split the application
- Use build.rollupOptions.output.manualChunks to improve chunking: 
https://rollupjs.org/configuration-options/#output-manualchunks
- Adjust chunk size limit for this warning via build.chunkSizeWarningLimit.
✓ built in 6.19s
/workdir
Error: Failed while trying to build all canisters.
Caused by: The build step failed for canister 'zgay6-caaaa-aaaai-rafkq-cai' (ic_vetkeys_encrypted_maps_canister)
Caused by: Failed to build Rust canister 'ic_vetkeys_encrypted_maps_canister'.
Caused by: Failed to compile the rust package: ic-vetkeys-encrypted-maps-canister

Let's fix these (and extend the ICP Ninja deployment workflow) in a separate PR.