Write up on some ways to publish extensions (#1660)

* write up on some ways to publish extensions
Signed-off-by: Sebastian Malton <sebastian@malton.name>

* tweak text
Signed-off-by: Jari Kolehmainen <jari.kolehmainen@gmail.com>
Co-authored-by: Jari Kolehmainen <jari.kolehmainen@gmail.com>

docs/extensions/testing-and-publishing/publishing.md

+# Publishing Extensions
+
+To be able to easily share extensions with users they need to be published somewhere.
+Lens currently only supports installing extensions from NPM tarballs.
+All hosted extensions must, therefore, be retrievable in a NPM tarball.
+
+## Places To Host Your Extension
+
+We recommend to host your extension somewhere on the web so that it is easy for people to search for and download it.
+We recommend either hosting it as an NPM package on https://www.npmjs.com or through GitHub releases.
+We recommend against using GitHub packages (https://github.com/features/packages) as it requires a GitHub token to access the package.
+
+### Publishing via NPM
+
+This is the easiest method of publishing as NPM comes built in with mechanism to get a link to download the package as a tarball.
+Once you have set up an account with NPM (https://www.npmjs.com/signup) and logged in with their CLI (`npm login`) you will be ready to publish.
+
+* Run `npm version <major|minor|patch>` to bump the version of your extension by the appropriate amount.
+* Run `npm publish` to publish your extension to NPM
+* Run `git push && git push --tags` to push the commit that NPM creates to your git remote.
+
+It is probably a good idea to put into your README.md the following instructions for your users to get the tarball download link.
+
+```bash
+npm view <extension-name> dist.tarball
+```
+
+This will output the link that they will need to give to Lens to install your extension.
+
+### Publish via GitHub Releases
+
+Another method of publishing your extensions is to do so with the releases mechanism built into GitHub.
+We recommend reading [GitHub's Releases Documentation](https://docs.github.com/en/free-pro-team@latest/github/administering-a-repository/managing-releases-in-a-repository) for how to actually do the steps of a release.
+The following will be a quick walk through on how to make the tarball which will be the released file.
+
+### Making a NPM Tarball of Your Extension
+
+While this is necessary for hosting on GitHub releases, this is also the means for creating a tarball if you plan on hosting on a different file hosting platform.
+
+Say you have your project folder at `~/my-extension/` and you want to create an NPM package we need to do the following within your git repo:
+
+```
+npm pack
+```
+
+This will create a NPM tarball that can be hosted on Github Releases or any other publicly available file hosting service.