Link with gravatar for a user account to pull their profile picture

[NathanCheshire]

JGravatar library for interaction with Gravatar.com is a bit outdated. We could make our own library separate from Cyder and pull it in with Gradle. Then others could easily use it, submit PRs, etc.

Notes:
Use builder pattern for API parameters
https://www.gravatar.com/avatar/HASH
.jpg sometimes required
default size is 80x80, allow customizing with config
?s=200
1-2048px range is valid
can supply own url to default image: ?d=https%3A%2F%2Fexample.com%2Fimages%2Favatar.jpg
d=404,mp,identicon,monsterid,wavatar,retro,robohash,blank are also valid options
force default image to always load: ?f=y
ratings: g, pg, r, x, can combine: g or pg use ?r=pg

[NathanCheshire]

https://en.gravatar.com/site/implement/hash/ instructions for hash. Link to documentation in source code so that if people want to PR, they know where an assumption originally came from.

[NathanCheshire]

/**
* A url parameter for a Gravatar request.
*/
public enum GravatarParameter {
    /**
    * The hash for a Gravatar request.
    */
    HASH(true),

    /**
    * The size of the image to be returned.
    */
    SIZE,

    /**
    * The URL to the default image to return in the case of a hash lookup failure.
    */
    DEFAULT_URL,

    /**
    * Whether to force the default url regardless of whether the hash can be located.
    */
    FORCE_DEFAULT,

    /**
    * The {@link GravatarDefaultPreset} type. Used to return a random custom avatar if a hash cannot be located.
    */
    DEFAULT_PRESET,

    /**
    * The default image URL a Gravatar request.
    */
    DEFAULT_IMAGE_URL,

    /**
    * The {@link GravatarRating} for a Gravatar request.
    */
    RATING;

    /**
    * Whether this URL parameter is required for a Gravatar request.
    */
    private final boolean required;

    GravatarParameter() {
        this(false);
    }

    GravatarParameter(boolean required) {
        this.required = required;
    }
}

[NathanCheshire]

https://en.gravatar.com/205e460b479e2e5b48aec07710c08d50.json can also get json data about a user
https://en.gravatar.com/site/implement/profiles/ for more information