Added extension sharing guidelines

[oruebel]

Add page with the general guidelines for sharing extensions

[bendichter]

My preference for names would be:

• the namespace name is e.g. "speech" (speech.namespace.yaml)
• the repo name is e.g. "ndx-speech" (git clone ...ndx-speech.git)
• the package name is e.g. "ndx_speech" (from ndx_speech import Transcription)

We know all non-core namespaces are going to be neurodata extensions, so there isn't much point in having the ndx prefix there. It only serves a purpose for the repo and package names, where this will be alongside other repos and packages.

[oruebel]

I think we need to clarify this text a bit, because I think it is not clear when we refer to the name of the namespace.yaml file and name key of the namespace that is in the namespace.yaml file. My current thinking is:

• The 1) name key of the namespace, 2) the name of recipe repo in the NDX catalog, and 3) the name of package in python should all be ndx_speech
• The name of 4) the yaml file of the namespace should be ndx_speech.namespace.yaml

If I understand it correctly, you are proposing to change (4) the name of YAML namespace file to just speech.namespace.yaml and leave (1 -3) as is with ndx_speech. I think that is probably fine.

I'll update the text to indicate _ instead of - as replacement for spaces to make sure we can have the same name for the python package and repos and namespace name.

[oruebel]

@bendichter I updated the text for "Naming namespaces and repositories". Does this look better?

[rly]

I updated the naming rules based on the discussion here: nwb-extensions/ndx-template#21

We can change it back, but my preference is:

1. the name key of the namespace should be ndx-speech
2. the name of the source repo and extension on PyPI is ndx-speech
3. the name of the record repo in the NDX catalog should be ndx-speech-record
4. the name of the package in python should be ndx_speech (hyphens not allowed)
5. the name of the namespace yaml file should be ndx-speech.namespace.yaml

Please see my reasoning in the above link.

[oruebel]

@rly I updated the terms to match and did some minor clean up. I think this one is good to go.

[rly]

I made a few changes:

• Require README file for release of extensions
• Mention that registration within the NDX catalog requires the name key of the namespace to begin with "ndx-"
• Do not say that the ndx-custom repository SHOULD include a URL (what would this URL point to?)
• Minor cleanup

I think this is good to go. Feel free to merge.