feat(deviceregistration): support security tokens, group assignment and templates

[reubenmiller]

Improvements/updates to the c8y deviceregistration commands

• register - Add --type and --group flags. The group flag can be used to assign a device to an existing group.
• approve - Add support for --securityToken flag and --template and --data flags
• getCredentials - No longer prompts for confirmation as it is more similar to a GET command (eventhough it is technically doing a POST under the hood)

Examples

# Register a device and assign it to a group
c8y deviceregistration register --id "ASDF098SD1J10912UD92JDLCNCU8" --group "Germany"

# Approve a device request with matching securityToken
c8y deviceregistration approve --id "1234010101s01ldk208" --securityToken "abcdef123456"

Resolves #430