Include `frint-props` and `frint-props-react`

[fahad19]

Include both the packages in docs sidebar.

[maryam-saeidi]

@fahad19 Where are the documentation of these packages? And in which section of the sidebar should the package names be included?

[fahad19]

Can be found in these places:

• https://github.com/frintjs/frint-props/tree/master/packages/frint-props
• https://github.com/frintjs/frint-props/tree/master/packages/frint-props-react

The links can go under Sidebar (under "PACKAGES" heading).