Add help options to pylero entrypoints

[leelavg]

• Add -h and --help options to pylero and pylero-cmd executables
• The implementation is attributed to how we are generating all the object even before prompting for user input
• Since, our entrypoints are triggered with no options by default, using any extra args other than help or using an option for our entrypoint is cumbersome

fixes: #107

Signed-off-by: Leela Venkaiah G lgangava@redhat.com

[waynesun09]

For the pylero-cmd sub commands could we also do something when the config does not exist For example:

$ pylero-cmd list --help
Traceback (most recent call last):
  File "/home/waynesun/.local/share/virtualenvs/pylero-xZ4TB2uX/bin/pylero-cmd", line 49, in <module>
    from pylero.cli.cmd import CmdList
  File "/home/waynesun/.local/share/virtualenvs/pylero-xZ4TB2uX/lib/python3.10/site-packages/pylero/cli/cmd.py", line 9, in <module>
    from pylero.document import Document
  File "/home/waynesun/.local/share/virtualenvs/pylero-xZ4TB2uX/lib/python3.10/site-packages/pylero/document.py", line 24, in <module>
    from pylero.work_item import _WorkItem
  File "/home/waynesun/.local/share/virtualenvs/pylero-xZ4TB2uX/lib/python3.10/site-packages/pylero/work_item.py", line 1580, in <module>
    cfg = Configuration()
  File "/home/waynesun/.local/share/virtualenvs/pylero-xZ4TB2uX/lib/python3.10/site-packages/pylero/base_polarion.py", line 105, in __init__
    raise PyleroLibException(
pylero.exceptions.PyleroLibException: The config files must contain valid values for: url, user, password and default_project

the user should get the subcommand help info even the config does not exist

[waynesun09]

Let's merge this and keep the sub-command issue in the original issue for tracking. Thanks!