rabbit_prelaunch_conf: Load additional Cuttlefish configuration files

By default, in addition to `$RABBITMQ_CONFIG_FILE`, we also load all
matching `$RABBITMQ_CONFIG_FILES`. It allows to split the configuration
into many files for easier management.

Here is the behavior in more details:

* If `$RABBITMQ_CONFIG_FILES` is a directory, all files directly inside
  it are considered.

* If `$RABBITMQ_CONFIG_FILES` is a glob pattern, all files matching the
  pattern are considered.

* In both cases, subdirectories (and whatever they contain) are ignored.

* `$RABBITMQ_CONFIG_FILES` is only relevant when the main configuration
  is either missing (the file does not exist or is empty) or uses the
  Cuttlefish format.

* Additional configuration files must use the Cuttlefish format.

The default value of `$RABBITMQ_CONFIG_FILES` is:
* `/etc/rabbitmq/conf.d/*.conf` on Unix
* `%APPDATA%\RabbitMQ\conf.d\*.conf` on Windows

Error messages related to Cuttlefish parsing were improved in the
process.

[#171491267]

0 files changed, 0 insertions, 0 deletions