ejsonDecryptWithKey filePath key
ejsonDecryptWithKey returns the decrypted content of an
ejson-encrypted file.
filePath indicates where the encrypted file is located, and key is used to decrypt the file.
The decrypted file is cached so calling ejsonDecryptWithKey multiple
times with the same filePath will only run through the decryption
process once. The cache is shared with ejsonDecrypt.
Example
{{ (ejsonDecryptWithKey "my-secrets.ejson" "top-secret-key").password }}