[meta] Add destination plugin documentation to the codebase

Let's add documentation to the migrate destination plugins, similar to #2776179: [meta] Add process plugin documentation to the codebase.

In particular some plugins now use a configuration parameter, for example, 'translations, and should be documented.

The destination plugins are;

High priority, uses configuration parameter(s).

• Config - #2862655: Add documentation to Config destination plugin
• Entity - #2862659: Add documentation to Entity destination plugin
• EntityConfigBase - #2862661: Add documentation to EntityConfigBase destination plugin
• EntityContentBase - #2862662: Add documentation to EntityContentBase destination plugin

Medium priority

• ComponentEntityDisplayBase - #2862741: Add documentation to ComponentEntityDisplayBase destination plugin
• DestinationBase - #2862743: Add documentation to DestinationBase destination plugin
• EntityBaseFieldOverride - #2862744: Add documentation to EntityBaseFieldOverride destination plugin
• EntityFieldInstance - #2862745: Add documentation to EntityFieldInstance destination plugin
• EntityFieldStorageConfig - #2862746: Add documentation to EntityFieldStorageConfig destination plugin
• EntityRevision - #2862748: Add documentation to EntityRevision destination plugin
• EntityViewMode - #2862749: Add documentation to EntityViewMode destination plugin
• NullDestination - #2862750: Add documentation to NullDestination destination plugin
• PerComponentEntityDisplay - #2862751: Add documentation to PerComponentEntityDisplay destination plugin
• PerComponentEntityFormDisplay - #2862752: Add documentation to PerComponentEntityFormDisplay destination plugin

Next Steps

1. Choose a plugin to document
2. Create patch in the child issue.