Add real example for how to add plugins

[sanjarcode]

ns plugin add @nativescript/secure-storage works.

The following don't:

npm install @nativescript/secure-storage

# or

ns plugin add secure-storage
``

[sanjarcode]

The same is missing from docs, and also doesn't work. See https://docs.nativescript.org/development-workflow.html#plugins

[uderline]

https://v8.docs.nativescript.org/plugins/imagepicker.html#intro gives the npm install command and it works for me

ns plugin add secure-storage doesn't work though because it's probably an old plugin. The provided link doesn't work btw