Fix swagger codegen typings

[koonpeng]

It seems the typescript-axios plugin does not generate correct typings, all the models have any type. The typescript-fetch plugin works as expected but is not immediately compatible with node without a "polyfill".

This get more important as we start to have more "custom" models. For example, the TaskProgress model is based off of rmf's TaskSummary message, with an additional field to indicate the current progress. These "custom" models are not reflected in rmf-models and must be imported from api-client. In the future, dashboard and react-component might not use rmf-models directly anymore, all model definitions will come from api-client.

We can either switch to typescript-fetch or attempt to fix typescript-axios upstream. Note that swagger codegen is a java project so that requires a different set of expertise.