Tutorial for TCR Front End

[JoshOrndorff]

Write a tutorial that takes the learner through the process of writing a custom front-end starting with the front-end template.

[JoshOrndorff]

We've decided to deprecate the old TCR tutorial and replace it with this one for building a custom front end. This tutorial should build a front end for this newer TCR code using the substrate-front-end-template as its starting point. It does not need to cover the rust code in much detail. This is basically the opposite of the build a dapp tutorial which covers rust code in details and just gives the user the front-end code.