SDO doc change to clarify the hzn voucher import --policy and -e flags

[bmpotter]

The documentation of the -e <example> flag of the hzn voucher import command is unclear about what it does and what else can be specified for <example>.

• Clarify in README-1.10.md what -e is doing (auto-generating a node policy) and what else can be passed into it.
• Add to README-1.10.md that alternatively --policy can be used to specify a node policy, or -p|--pattern can be specified to use a pattern.
• In both cases above, clarify that they need deployment policies that correspond to the node policy
• Backport the doc changes that are applicable to README-1.8.md
• Add these tasks to SDO-support issue 61: change the hzn help info with similar information, validate the pattern exists in hzn voucher import --pattern=<pattern>, and validate the schema of the node policy in hzn voucher import --policy=<node-policy-file>

[bmpotter]

Glen reviewed/approved the doc changes.