feat(example): add rust custom provider template

[brooksmtownsend]

Feature or Problem

This PR adds a "blank slate" capability provider that's purpose made to inform deeply how to use the wasmcloud-provider-sdk, and where each piece fits into implementing a custom provider. I've included a test component as well in order to try out the provider, and a few workflows to get started quickly with writing and debugging a custom capability.

There will be two followups to this PR:

1. Mirroring this exact example with the provider-sdk-go, and a tinygo component, to give another comprehensive guide
2. Documentation on https://wasmcloud.com on the workflow that I have in mind, being 1. use wash new to generate this template, 2. update the WIT to fit a custom interface based on an idea, 3. implement the new logic, 4. run

edit: renamed all instances of "blank slate" to "custom template" to better indicate the purpose.

Related Issues

Release Information

Consumer Impact

Testing

Unit Test(s)

Acceptance or Integration

Manual Verification

I ran through these READMEs and the application flow, but more testing is appreciated!

[vados-cosmonic]

Hey @brooksmtownsend what do you think about the name? blank-state is OK but maybe... template or example might be nice?

[brooksmtownsend]

@vados-cosmonic Honestly I'm not too dedicated to blank slate 😄 Template is good, I think just something that provides the message that this is a sample but meant to be used as a "base" for a custom provider is perfect

[vados-cosmonic]

Oh also another thing I was thinking is that this is will be an input to wash new right? so a more generic name like that might be very useful/good for docs

[brooksmtownsend]

Oh also another thing I was thinking is that this is will be an input to wash new right? so a more generic name like that might be very useful/good for docs

Good point. Perhaps it could be custom-template, is that too generic?

[vados-cosmonic]

Hmnnn IMO just template works fantastic there -- wash new provider template is pretty intuitive looking...

Though I can think of some others?

wash new provider boilerplate
wash new provider skeleton?

template makes more sense as a folder name in the repo, but skeleton or boilerplate make more sense on CLI... maybe we can just alias those other names to template.

[brooksmtownsend]

Ooh I do like the idea of wash new provider myprovider -t template-rust or wash new provider myprovider -t template-go

[vados-cosmonic]

This is awesome, fantastic example for building providers!

LGTM 🚀