Manage tokens

[tschubotz]

Story
As a user I can decide which tokens to display in order to be able to focus only on the ones I own.

Acceptance criteria

• Please pull the token list from the same source like the Personal Edition clients
• Tokens are sorted ascending by token symbol
• User can enable and disable each token
• User can search by name and symbol
  • Ideally, the search would be automatically triggered, after each entered character.
  • Clearing the search field displays all tokens again.
• Closing the modal bring the user back to the Safe overview with the token selection applied.

[tschubotz]

Removed custom tokens from this issue @apanizo