Added Vale linter bot

[ppansare]

Addresses Issue #5876

Added Vale linter bot to search for and replaces incorrect spellings of Read the Docs including RTD and Read The Docs. Linter bot also checks for spelling errors and repetitions.

Co-Author: @IvanMart57 Co-Author: @Melodyncr

Reference: https://www.shwetashetye.com/blog/vale/

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:books: Documentation previews :books:

• User's documentation (docs): https://docs--9521.org.readthedocs.build/en/9521/

• Developer's documentation (dev): https://dev--9521.org.readthedocs.build/en/9521/