Fixes for a couple of bugs

[temi]

1. Bulk indexing MongoDB documents are very slow #169
2. Properties mapping of string fields to ES type keyword not working as expected #170

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[CLAassistant]

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[puneetbehl]

Please sign the CLA.

[temi]

@puneetbehl it is now signed

[puneetbehl]

@temi I am sorry but I no longer have access to merge the pull-request.

[temi]

@puneetbehl is this something I can help with?

[puneetbehl]

I don't know but another option is to merge back to my private GitHub account and do a release that would change the group id to io.github.puneetbehl:elasticsearch. Alternatively, you can fork it to your private GitHub account and publish from there.

Please let me know how can I help.