Unify command-line importer help

- Use OMERO username and OMERO password
- Capitalize ID across the board
Group all Java arguments into a group for parsing clarity

- Also use METAVAR for annotation key/value pairs
Improve readability of importer-cli usage() method
Improve description of Java importer arguments

- Move -f option to the list of optional arguments
Add logic to define epilogs in CLI parsers
Define examples at the epilog of the help and add link to documentation

Also unify the examples and show additional option usages (-f, --debug)
Use path instead of arg for the positional argument
Use path in the usage() of Java command line import
Fix test_import.py clitest to account for new epilog keyword
Expose plate name/description arguments and group naming arguments
Reorganized grouping/description of command-line importer argument
Move the optional login arguments up in the import help
Align optional arguments
Fix example image names in import.py
Merge pull request #2154 from sbesson/rebased/develop/12010_cli_usage

Unify command-line importer help (rebased onto develop)