As a contributor I want to facitate model/dependency management for UDFS

[HansVRP]

Follows from the discussion in: ESA-APEx/apex_algorithms#44

There is a lot of repeated code on downloading's and unzipping dependencies/models for UDFs.

As a user it would be easier to if this functionality is standardized

[HansVRP]

@soxofaan

[JeroenVerstraelen]

First steps: discuss and create plan.

[jdries]

Options:

• python API that is available backend side to handle common tasks, this has standardization impact
• allow to 'stage in' specific files from user workspace

[soxofaan]

The idea of the discussion at ESA-APEx/apex_algorithms#44 that triggered this ticket is to extract and streamline the reusable boilerplate from https://github.com/ESA-APEx/apex_algorithms/pull/44/files#diff-e4675798e612393458d512e82ec49d1083fe90012bd506f1f2e05c971d0bcac4

[HansVRP]

I mainly see 2 usecases:

1. passing models along a UDF to use them in the cloud.
2. passing additional files with code you want to use within your udf, instead of needing to place everything in it