[prosEO CLI] UX: Order>subcommand - addition of a definition of the statuses about proseo

[tangobravo62]

Updated help text to include order status list and effects of order commands on order status:

prosEO> order -h
Commands for managing processing orders; some commands can only be issued, if the order is in the correct status. Order status sequence is Initial - Approved - Planned - Released - Running - Completed/Failed - Closed. Additionally an order may be in status "Suspending" after issuing a "suspend" command, until all running job steps are finished.
Options:
    -h, --help        Show help information for the current command level (top level commands, when called from the shell command line)
Positional parameters:
    -- none --
Subcommands:
    show              Lists orders, optionally restricted to a given time range or a specific processing order
    create            Create a new processing order (in status Initial); if the input is not from a file, the user will be prompted for mandatory attributes not given on the command line
    update            Update a processing order (only allowed in status Initial)
    approve           Approve the named processing order for planning (must be in status Initial, new status is Approved)
    plan              Plan the jobs for the named processing order (must be in status Approved, new status is Planned)
    reset             Reset the named processing order to initial state (must be in status Approved or Planned, new status is Initial)
    release           Release the jobs of the named processing order for processing (must be in status Planned, new status is Released; order status will change to Running, when execution of the first job step starts; when all job steps are finished, the status will change again to Completed, if all job steps finished successfully, or Failed, if at least one job step failed)
    suspend           Suspend starting of further jobs for the named processing order (must be in status Released or Running, new status is Suspending, then Planned, when all running job steps are finished)
    resume            Resume starting of jobs for the named processing order after suspend (order must be in status Planned, new status is Released [actually the same command as "release"])
    cancel            Cancel the named processing order (remaining jobs are not executed, order state changes to Failed; order must be in status Planned, i. e. it may be necessary to issue a "suspend" command first)
    close             Close the named processing order (must be in status Completed or Failed, new status is Closed)
    delete            Delete the named processing order (only allowed in status Closed)

@dlr-tangosierra : Please check whether this answers the request.