Update issue templates, commitcheck and Contributing.md

Update issue templates, commitcheck and Contributing.md

- Removes OpenZFS ports from commit check
- Removes OpenZFS ports from CONTRIBUTING.md
- Adds mailings lists and IRC to issue template selector
- Remove blank issue option from issue creator

Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>
Closes #10965