Docs for SERVER-35044: Remove maxScan query option

Description:

For our MongoDB 4.2 documentation:

1. Remove existing documentation that references maxScan and $maxScan. Where appropriate refer to maxTimeMS as a means for putting a limit on command execution.
2. Add a note to the 4.2 compatibility notes stating that maxScan and $maxScan have been removed from the server. This note should recommend maxTimeMS as an alternative.

Scope of changes:

• rm cursor.maxScan +source/includes/apiargs-method-cursor.maxScan-param.yaml
  • source/includes/ref-toc-method-cursor.yaml
• rm $maxScan meta operator
  • source/includes/ref-toc-operator-meta.yaml
• find command
• rm reference in:
  • source/includes/extracts-mongo-shell-deprecated-meta-operator.yaml
  • modified: source/release-notes/4.0-compatibility.txt
  • modified: source/reference/command/find.txt
  • modified: source/includes/apiargs-dbcommand-find-field.yaml
• 4.2.txt
• 4.2-compatibility

Impact to other docs outside of this product:

none

MVP:

Resources: