Fixes Issue #91 - Clean up markdown

[jischr]

Using a markdown linter (https://github.com/DavidAnson/markdownlint/tree/v0.37.4), i cleaned up our markdown files. all has been tested running the make command.

I overwrote some of the default linter settings in .markdownlint.yaml that didn't align with kramdown-rfc/xml2rfc generators

I cleaned up the markdown for the following files:

• openid-caep-1_0.md
• openid-caep-interoperability-profile-1_0.md
• openid-sharedsignals-framework-1_0.md
• working-group-charter.md

I also opened #264 to update RISC to use md as source of truth rather than xml for easier maintenance

[jischr]

Fixes #91

[tulshi]

@appsdesh please review the changes to the interop spec.