Add a web share target

[pomdtr]

Adding the ability to directly share a link from the browser to workflowy on android would be awesome.

Here is some documentation on the api : https://web.dev/web-share-target/ And here is some more general informations on the pwa manifest file: https://web.dev/add-manifest/

[cjlm]

Thank you for this, I shall try to add it in the next release.