Replace localStorage usage with drift tables (#1045)

[SleepySquash]

Resolves #1045

Synopsis

Currently localStorage is used to synchronize some data between Web tabs. However, we now have drift database, which does the synchronization without any need to use workarounds.

Solution

Replace the localStorage usage with drift:

• Remove credentials_* related usage.
• Replace call_* related usage with drift tables.
• Replace prefs_call_* related usage with drift tables.

Checklist

• Created PR:
  • In draft mode
  • Name contains issue reference
  • Has type and k:: labels applied
• Before review:
  • Documentation is updated (if required)
  • Tests are updated (if required)
  • Changes conform code style
  • CHANGELOG entry is added (if required)
  • FCM (final commit message) is posted or updated
  • Draft mode is removed
• Review is completed and changes are approved
  • FCM (final commit message) is approved
• Before merge:
  • Milestone is set
  • PR's name and description are correct and up-to-date
  • All temporary labels are removed

[SleepySquash]

In order to understand whether there's any tabs of the Web application opened at all, we should implement a mechanism based on the localStorage to properly monitor the tabs being opened and closed. Why do we need it? For example, to understand whether there's any calls happening in the popups: if there are, then should consider the call as active. Without that user might close the popup before it even initializes any Dart code, which will make the call stuck.