* nxos_snmp_user: platform fixes for get_snmp_user
snmp user output behavior varies quite a bit for the different nxos platforms and required several workarounds:
- N5K/N6k
- These platforms do not support structured output for `show snmp user`.
- The current code lands in an `except` clause when the output is not structured; so I added a new `get_non_structured_snmp_user` method to scrape the state from the regular cli output if it's present.
- N9K-F
- The `group` data in the JSON output is different for this platform; it has a different key (just `group` instead of `TABLE_groups` or `group_names`) and it is not indexed
- For a single group the value is a string, for multiple groups it's a list
- sanity
- N5K/N6K/N9K-F platforms will reject `no snmp user <name> <role>` when it's the last role defined for the user.
- workaround is to use `nxos_user` to remove the user
- Changes validated on:
- `N3K, N3K-F, N35, N6K, N7K, N9K, N9K-F`
- `6.0(2)A8`
- `7.0(3)I2, 7.0(3)I4, 7.0(3)I5, 7.0(3)I6, 7.0(3)I7`
- `7.3(2)D1`
- `7.3(3)N1, 7.3(4)N1`
- `8.3(2)`
- `9.2(2), 9.2(3)`
* fix lint warning
8c56c116e5