refactor: updated README file to reflect template changes

[Mashal-m]

The README of the MFE's needs to be updated because the frontend app template has been updated.

Issue related: https://github.com/openedx/wg-frontend/issues/169

[codecov[bot]]

Codecov Report

All modified lines are covered by tests :white_check_mark:

Comparison is base (e2ccd1b) 89.09% compared to head (f80f2d7) 89.09%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #341 +/- ## ======================================= Coverage 89.09% 89.09% ======================================= Files 6 6 Lines 55 55 Branches 18 18 ======================================= Hits 49 49 Misses 6 6 ```

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