Move Docs repository travis pipeline to circleci

Description

The [docs repository](https://github.com/mattermost/docs) today uses travis ci to build and deploy the docs website.
We would like to move that to circleci as part of our migration to circleci

This ticket is about create the new pipeline to do the same steps we have for travis but on circleci.

note: you can use the aws-s3 circleci orb for the copy
note2: you can reach @cpanato in our community server to talk about the secrets and enable the repository on circleci

QA Test Steps

No testing required.

Status

Mana

None

Assignee

Unassigned

Reporter

Carlos Panato

Epic Link

None

Fix versions

Mattermost Team

Cloud

Sprint

None

Labels

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