GEODE-7955: Docs for redundancy internal API and redundancy commands

[DonalEvans]

• Document restore redundancy gfsh command
• Document status redundancy gfsh command
• Document new RestoreRedundancyOperation API usage
• Add rebalance and restore redundancy stats to stats list
• Removed suggestion to use show metrics command to determine redundancy
  status
• Removed suggestions to use rebalance when only restoring redundancy is
  wanted

Authored-by: Donal Evans doevans@pivotal.io

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[davebarnes97]

Editorial suggestions.

• In geode-subnav.erb:

href="/docs/guide/<%=vars.product_version_nodot%>/tools_modules/gfsh/command-pages/restore.html">restore

Make the topic "restore redundancy" (this follows a convention already in use)

• In checking_region_redundancy.html.md.erb:

"First, starting a gfsh prompt and connect..." should be "Start gfsh and connect..."

• In rebalancing_pr_data.html.md.erb:

Rebalancing solely for the purpose of restoring lost redundancy in the
case that redundancy is being used for high availability and the
region has been configured to not automatically recover redundancy
after a loss is not necessary.

Reword slightly and add commas:

Rebalancing solely for the purpose of restoring lost redundancy, when
redundancy is being used for high availability and the
region has been configured to not automatically recover redundancy
after a loss, is not necessary.

• In restoring_region_redundancy.html.md.erb:

Paragraph 2:

"Restoring redundancy will create new redundant copies..."
"It will not move buckets..."

Rephrase these sentences from future to present tense:

"Restoring redundancy creates new redundant copies..."
"It does not move buckets..."

• In restore.html.md.erb:

behaviour -> behavior

• In status.html.md.erb:

Add an entry for the newly-added "status redundancy" topic to the bullet list at the top of the page. (follow format of other entries)

[davebarnes97]

+1 LGTM