doc: add description and build instructions for using devcontainers

Signed-off-by: pavelbezpravel <[email protected]>

doc/building-devcontainer.md

@@ -0,0 +1,20 @@
+## Building seastar using devcontainers
+
+A development container (or devcontainer for short) allows you to use a container as a full-featured development environment. It can be used to run an application, to separate tools, libraries, or runtimes needed for working with a codebase, and to aid in continuous integration and testing.
+
+You can build a project with [devcontainers](https://containers.dev/) in an easy and convenient way.
+Your IDE (e.g. Clion) or code editor (e.g. VS Code) can run and [attach](https://containers.dev/supporting) to devcontainer.
+
+Also you can use [devcontainers/cli](https://github.com/devcontainers/cli) to set up environment and build the project manually via bash:
+
+```bash
+devcontainer up --workspace-folder .
+
+devcontainer exec --workspace-folder . \
+ ./configure.py --mode=release
+
+devcontainer exec --workspace-folder . \
+ ninja -C build/release
+```
+
+It's just a more powerful and convenient version of [building-docker](./building-docker.md)