mod_http_oauth2: Add role selector to consent page List includes all roles available to the user, if more than one. Defaults to either the first role in the scope string or the users primary role. Earlier draft listed all roles, but having options that can't be selected is bad UX and the entire list of all roles on the server could be long, and perhaps even sensitive. Allows e.g. picking a role with fewer permissions than what might otherwise have been selected. UX wise, doing this with more checkboxes or possibly radio buttons would have been confusion and/or looked messier. Fixes the previous situation where unselecting a role would default to the primary role, which could be more permissions than requested.

Contributing
============

Guidelines for developers
-------------------------

-   Each module should be contained in a folder of its name (e.g.\
     `mod_ping/mod_ping.lua`)
-   Each module should have a `README.markdown` page in their folder
    with a description, usage, configuration and todo sections (feel
    free to copy an existing one as a template)
-   Commit messages should begin with the name of the plugin they are
    for (e.g. `mod_ping: Set correct namespace on pongs`)

Instructions on cloning the repository are at
<https://prosody.im/doc/installing_modules#prosody-modules>