docs: add API versions v1.30 - v1.37

Adding separate documents for older API versions, so that these don't have to
be collected from each tag/release branch. For each version of the API, I picked
the highest release that uses the API (to make sure to include possible fixes
in the swagger);

    git mv api/swagger.yaml api/swagger-current.yaml

    git checkout v18.05.0-ce -- api/swagger.yaml
    git mv api/swagger.yaml docs/api/v1.37.yaml

    git checkout v18.02.0-ce -- api/swagger.yaml
    git mv api/swagger.yaml docs/api/v1.36.yaml

    git checkout v18.01.0-ce -- api/swagger.yaml
    git mv api/swagger.yaml docs/api/v1.35.yaml

    git checkout v17.11.0-ce -- api/swagger.yaml
    git mv api/swagger.yaml docs/api/v1.34.yaml

    git checkout v17.10.0-ce -- api/swagger.yaml
    git mv api/swagger.yaml docs/api/v1.33.yaml

    git checkout v17.09.1-ce -- api/swagger.yaml
    git mv api/swagger.yaml docs/api/v1.32.yaml

    git checkout v17.07.0-ce -- api/swagger.yaml
    git mv api/swagger.yaml docs/api/v1.31.yaml

    git checkout v17.06.2-ce -- api/swagger.yaml
    git mv api/swagger.yaml docs/api/v1.30.yaml

    git mv api/swagger-current.yaml api/swagger.yaml

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 2b8ae085719d0199bc352d86f62cac057e3e79b3)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Upstream-commit: 9f5a5da4cbc6bf75bab7feb50662caf6f77a885f
Component: engine

Author: thaJeztah