Add Cloud Providers section (#202)

Migrates the cloud providers listed in the Gitea docs (installation/on-cloud-provider) into the awesome list: alwaysdata, Cloudron, Exoscale, Linode, Sealos.

Reviewed-on: https://gitea.com/gitea/awesome-gitea/pulls/202
Reviewed-by: Zettat123 <39446+zettat123@noreply.gitea.com>

README.md

@@ -26,6 +26,7 @@ Entries are grouped by maintenance status:
       - [DevOps](#devops)
       - [Mobile](#mobile)
       - [Web Hosting](#web-hosting)
+    - [Cloud Providers](#cloud-providers)
     - [Migration](#migration)
     - [Organizations](#organizations)
       - [Open Registration](#open-registration)
@@ -134,6 +135,14 @@ Zenith Hosting offers Gitea as a one-click deployment option on the platform. Th
 - [Pages Server](https://github.com/d7z-project/gitea-pages) - Another opinionated gitea pages project. GitHub-compatible with custom template rendering support. `Apache-2.0` `Go`
 - [gitea-pages](https://github.com/deadnews/gitea-pages) - A static pages server for Gitea with minimal dependencies. `MIT` `Go`
 
+### Cloud Providers
+
+- [alwaysdata](https://www.alwaysdata.com/en/marketplace/gitea/) - Gitea is available as an app in the alwaysdata marketplace.
+- [Cloudron](https://cloudron.io/button.html?app=io.gitea.cloudronapp) - 1-click Gitea install on Cloudron; the package is maintained at [git.cloudron.io](https://git.cloudron.io/cloudron/gitea-app).
+- [Exoscale](https://www.exoscale.com/marketplace/listing/glasskube-gitea/) - European cloud provider offering Gitea managed by Glasskube in its marketplace.
+- [Linode](https://www.linode.com/marketplace/apps/linode/gitea/) - Gitea is available as an app in the Linode Marketplace.
+- [Sealos](https://sealos.io/products/app-store/gitea) - One-click Gitea deployment from the Sealos app store.
+
 ### Migration
 
 - [BitbucketServer2Gitea](https://github.com/appleboy/BitbucketServer2Gitea) - A command line tool build with Golang to migrate a Bitbucket Server (Stash) Project to Gitea. `MIT` `Go`