Add first version of CHANGELOG

Update contributing guide with steps before issuing a new release

CONTRIBUTING_GUIDE.md

@@ -42,3 +42,17 @@ This document contains some rules you should adhere to when contributing to this
 * Do not taint this repository with incompatible licenses: everything not MIT-licensed
   must be kept external to this repository.
 
+## Releasing
+
+When creating a new release follow the steps below:
+
+- Run `scripts/add_spdx_headers.sh` from each crates to update the SPDX headers.
+- Update relevant document in [README.md](README.md) and [documentation](documentation).
+- Use [semantic versioning](https://semver.org/) for the new tag.
+- Update [CHANGELOG.md](CHANGELOG.md) following the guidelines [here](https://keepachangelog.com/).
+- Make sure that
+  - New contributors have been added to `CONTRIBUTORS.txt`.
+  - All tests and checks succeed with `cargo test`, `cargo fmt --check`, and
+    `cargo clippy`.
+  - All the functions build correctly with `scripts/functions_build.sh`.
+  - All the examples work with `scripts/run_all_examples.sh`.

README.md

@@ -118,15 +118,15 @@ Some components/features are illustrated separately:
 
 Currently there are several known limitations, including the following ones:
 
-- the dataplane within an orchestration domain is realized through a full-mesh
-  interconnection between all the nodes and the ε-BAL;
+- the dataplane is limited within a single orchestration domain and realized
+  through a full-mesh interconnection between all the nodes;
+- the ε-BAL is a mere skeleton with no logic;
 - the ε-CON only supports a single orchestration domain and does not perform
   any kind of admission control;
 - no workflow-level annotations are supported; 
 - the payload of events is not encrypted;
-- the configuration of the ε-CON, ε-CON, and ε-BAL is read from a file and
-cannot be modified (e.g., it is not possible to add an orchestration domain
-or a node while running);
+- the configuration of the ε-CON is read from a file and cannot be modified
+  (e.g., it is not possible to add an orchestration domain);
 - there is no persistence of the soft states of the various components.
 
 The full list of issues is tracked on