Rename this repo to learner-home

[ghassanmas]

The configuration/toggles for this MFE are referred as mfe_home however the repo name is leaner-dashboard.

This might create confusion. as typically (as observed) the pattern that is uesed that toggles/settings for each MFE are named as to what the MFE is called in it's repo.

So I suggest either:

1. rename this repo to frontend-app-leaener-home
2. rename its related toggle namespace to learner_dashboard