[Docs]Flesh out complete documentation on how to extend Flytekit

[kumare3]

Describe the documentation update
Flytekit can be extended in multiple ways

• Type Extensions as somewhat explained here
• SDK side task extensions, as somewhat explained here

Ideally this section should provide the user all the tools and links needed to extend flytekit for their needs.

An important note that should be emphasized is When to extend only flytekit - as documented here. There is actually a flowchart that explains when to extend flytekit.

A good example of writing a flytekit only plugin can be documented for SQLite3 plugin, which is a core plugin code here

An example usage for this task is available here

[smariotti]

I'll be happy to have a look at this!

[SandraGH5]

@samhita-alla @cosmicBboy Is this part of the current documentation revamp plan?

[cosmicBboy]

we haven't specifically accounted for this issue yet in the docs revamp RFC, however it should be fairly straightforward to map it into the Extending Flyte section in the detailed hierarchy

This issue should ideally happen after docs have been re-structured by @samhita-alla

[cosmicBboy]

Closing this as it's redundant with #1541.

This section in flytesnacks is the entrypoint for user guides relating to extending flyte.