login: suggested issuers

[angelo-v]

WIP to implement part of #21 - using a modal dialog instead of prompt allows browser's built-in autocomplete to be used and provided platform for further features

• Create modal in pos-login & display modal on click - now waiting on refactor: split out pos-dialog #23
• Duplicate functionality of getIdpUrl, i.e. a single input textbox with a default value
• Style pos-login-form
• Tests have been written
  • all new code is covered by unit tests
    • Add test for pos-login-form
    • Edit tests for pos-login
      • pos-login.spec.tsx
      • pos-login.integration.spec.tsx
  • the happy path of a new feature is covered by an end-to-end test
    • Add new e2e test in https://github.com/pod-os/PodOS/tree/main/apps/tests
  • manual explorative tests have been performed
• all dependencies are updated to the latest patch version at minimum
  • Done upstream
• the CI pipeline passes
• documentation is up-to-date
  • TSDoc style comments on important functions, properties and events
    • Documented onIdpUrlSelected event
  • stories for new PodOS elements have been added to storybook
    • No changes required to https://github.com/pod-os/PodOS/blob/main/storybook/stories/login/1_pos-login.stories.mdx
  • Readme.md files of PodOS elements have been re-generated
    • npm run build in elements
  • architectural decisions are documented as an ADR
    • No new architectural decisions
  • Changelogs are updated according to Keep a Changelog
• Possibly rename onIdpUrlSelected event

Edited 29 Jul to reduce scope of this PR. See #21 for backlog checklist

[angelo-v]

supersedes #22