Merge pull request #6575 from EnterpriseDB/bugfix/josh/DOCS-984-the-d…

…ocs-playground-is-visible-in-searches-on-goog

DOCS-984: hide the Docs playground section from Google

Docs 769-b (#6505)

* Small fixes for new upgrade command.

* Updates for 5.7

* Added a note about upgrading both PGD version and Postgres major version simultaneously with pgd node upgrade.

* small changes

* Added a note about upgrading to older versions than 5.7.0 of PGD and using bdr_pg_upgrade instead.

* updated upgrade paths to include 4.37 to 5.7.0

* Small changes

* Took reconcile with TPA bit out as it no longer works.

* added redirect

* Fixed redirect and changed filename.

* Small changes in language to show you can upgrade both major versions of PGD and Postgres.

* Small changes in index.

* Some link fixes.

* some small changes