docs: add Discord link and maintainers file

Signed-off-by: inge4pres <fgualazzi@gmail.com>

Author: inge4pres

MAINTAINERS.md

@@ -0,0 +1,11 @@
+### Overview
+
+This document contains a list of maintainers in this repo. If you're interested in contributing, and becoming a maintainer, join the [Discord](https://discord.gg/5TzezG2n) server and introduce yourself.
+
+### Current Maintainers
+
+| Maintainer         | GitHub ID                                                |
+| ------------------ | -------------------------------------------------------  |
+| Francesco Gualazzi | [@inge4pres](https://github.com/inge4pres)               |
+| Giovanni Panice    | [@kmos](https://github.com/kmos)                         |
+| Hendrik Nielaender | [@hndrk](https://github.com/hndrk)                       |

README.md

@@ -83,3 +83,7 @@ You can read more about the original proposal and discussion at:
 https://github.com/open-telemetry/community/issues/2514
 
 For a more in-depth read of why OpenTelemetry needs a Zig SDK, see ["Zig is great for Observability"](https://inge.4pr.es/zig-is-great-for-observability/).
+
+## Join the community
+
+You can find the Zig OTel SDK developers in the [Zig-o11y Discord server](https://discord.gg/5TzezG2n).