ByChunks(): Execution of 'autosubmit expid' is not consistent with 'autosubmit create' and 'autosubmit run'

ByChunks_autosubmit.R has the parameter autosubmit_server:

#'@param autosubmit_server A character vector indicating the login node of the 
#'  autosubmit machine. It can be "bscesautosubmit01" or "bscesautosubmit02". 
#'  The default value is NULL, and the node will be randomly chosen.

When an experiment is run, the function connects via ssh to the autosubmit_server and runs the autosubmit create <expid> and autosubmit run <expid> commands.

If an Autosubmit expid is not specified, the function is supposed to create an experiment for the user by running the autosubmit expid command. However, this command is run locally, without connecting to autosubmit_server first, and therefore it will not work if the autosubmit module is not already available.

These differences lead to the workflow not running smoothly if the experiment is not previously created.

Since there are also cases where one can run autosubmit outside of the bscesautosubmit0x machines, which will be decomissioned at some point in the future, ByChunks() should be modified to:

2. If autosubmit_server is NULL, the commands should be run locally instead of ssh-ing to one of the machines randomly.
3. Run the expid, create and run commands in a consistent way on the same machine.