* - minor refactor of 'description' -> 'typeDescription' for
  generic processor descriptions
- added initial pass of generated descriptions for all processors

* fix i18n

* added wrapping div and title to description and changed default description to appear as placeholder

* reworked the description width and overflow styling

* only show the text title on hover when we are not showing the text input

* fixed a number of minor issues with using values as though they are strings and doing better serialization

* slight optimisation to scss

* - implement copy feedback
- clean up a lot of uses of "target_field = field". it is better
  to not show these
- made "replacement" a required field on gsub (which it was not)

* revert the previouis validation as empty values are acceptbale for the replacement text

* - updated the copy per feedback and fixed a missing i18n.translate
- slight update to SCSS classes to not have unused class

* Added an empty string field validator that accepts spaces so that
the KV processor value and field split fields accept " "

* replace use of HTML "title" with EuiToolTip

* remove unused variable and import

* implemented feedback; removed if from default descriptions and other minor updates

* update default description of foreach to always display

Co-authored-by: Kibana Machine <[email protected]>