See: #509

Closes: #510 - configuration file
Closes: #514 - command-line usage
Closes: #519 - HTTP service
Closes: #520 - jobs execution system
Closes: #529 - shared folder

This commit adds a new crate under `crates/ci-doc-updater` which can be
used to update source code blocks inside markdown files. For doing that,
it uses begin and end markers that are present in the file, and replaces
the text in between these markers. This is a very basic approach, and
its implementation is not too memory-efficient, but I expect it to be
robust enough for the use case, especially because the documentation
files are not very large. Through that mechanism, developers can get
notified by CI pipelines whenever any of the output changed and needs to
be updated inside the markdown documentation.

The `ci/docs-update-generated-parts.sh` script file was added. It
calls the `opentalk-controller` executable several times with different
command-line arguments in order to generate the output which...