[Core Feature] A blob store reference to TaskTemplate should be an available option to commandline

[kumare3]

Motivation: Why do you think this is important?
It is possible to completely encapsulate all logic of a task into a task template and it is possible to execute such a task, without needing to build a container. But, for this it should be possible to retrieve the task template without re-hydrating the code.
This is especially important for self-contained tasks like SQL queries, or ML scripts

Goal: What should the final outcome look like, ideally?
Flytekit or other SDK's could request for tasktemplate to be a command line parameter and FlytePropeller should fill this in with a blob store reference

Describe alternatives you've considered
This is currently only possible if you build the task into the container.

[Optional] Propose: Link/Inline OR Additional context
flytekit could create a modified command line that can accept a new parameter like --task-template {{ .tasktemplate.path }}
Flytepropeller's template resolution engine, can then substitute this with a reference to a blobstore.

[kumare3]

This is now merged and will be part of the platform release v0.12.0