Add rstats templates

[psolymos]

Signed-off-by: Peter Solymos psolymos@gmail.com

I created R/rstats templates using different HTTP frameworks and base images. I've decided to add the following 2 to the templates.json file of the store repository for the following reason:

• rstats-minimal: vanilla R + classic watchdog on Alpine base image, should be suitable as the smallest build for text/JSON based functions not needing additional R functionality
• rstats-base-plumber: R with plumber package installed + of-watchdog on Debian base image, this is the most versatile, plumber is mature with great community support and easy to add serializers/parsers through code annotation.

The https://github.com/analythium/openfaas-rstats-templates repository has other templates that might not be all suitable for mainstream consumption. The repo also has detailed documentation and an increasing number of examples.

R templates was discussed previously on Slack and offline, thanks for the great feedback.

I opened the related #114 request previously.

[alexellis]

Hi Peter,

Is this template multi-arch?

Alex

[alexellis]

The command "jq empty store.json" exited with 0.
0.01s$ jq empty templates.json
parse error: Expected separator between values at line 362, column 5
The command "jq empty templates.json" exited with 4.
```

It seems like the build is failing. Can you look into it please?

[psolymos]

Thanks @alexellis for having a look. I haven't tested multi-arch with these templates. Should I try docker buildx as described here? What's the preferred way to test it?