Make use of the new "label" property in the TokenDetails

[anxolin]

Intro to the issue:

• The token symbols are displayed in many parts of the app
• Normally, the token is modeled as a TokenDetail which has all the info from the ERC20 token plus some additions (like ID, or if the token is deprecated)
• Not all the tokens have symbol, this is inherited from the ERC20 standard
• To be able to always display a label for every token, even if it doesn't have a symbol, we make use of safeTokenName wich has some fallback options to always return a string
• The token list is cached, so once we construct this detailed representation of a Token, we don't recreate it over and over
• Every time we debug tokens, or display tokens we are handing the case where the symbol is undefined or we use the safeTokenName over and over

Now, this PR: https://github.com/gnosis/dex-react/pull/1513/files

• Added a mandatory label to the TokenDetails, just for convenience (for the problem above)
• In the PR was used only for sorting the tokens Alphabetically

Now we get to the point where I can explain what this issue is about :)

Let's make use of the label in the app, so we don't habdle "over and over" the same logic for displaying tokens. 😀