Add OCONUS Metadata for NEHRP 2020

Update metadata.js file with new regions for each data set. Note that these may collide with existing regions. We've dealt with that in the past with using _2P or _10P suffixes on the standard region names. Be consistent across other endpoints with this naming convention.

@nluco Please provide the following metadata and comment when this is ready.

Alaska (AK)

{
  modelVersion: 'v5.0.x',
  pgadFloor: Number,
  pgadPercentileFactor: Number,
  sadFloor: [Number0p0, ..., Number10p0],
  sadPercentileFactor: [Number0p0, ..., Number10p0],
  maxDirectionFactor: [Number0p0, ..., Number10p0],
  spatialInterpolationMethod: 'String'
}

American Samoa (AMSAM)

{
  modelVersion: 'v5.0.x',
  pgadFloor: Number,
  pgadPercentileFactor: Number,
  sadFloor: [Number0p0, ..., Number10p0],
  sadPercentileFactor: [Number0p0, ..., Number10p0],
  maxDirectionFactor: [Number0p0, ..., Number10p0],
  spatialInterpolationMethod: 'String'
}

Guam (GNMI)

{
  modelVersion: 'v5.0.x',
  pgadFloor: Number,
  pgadPercentileFactor: Number,
  sadFloor: [Number0p0, ..., Number10p0],
  sadPercentileFactor: [Number0p0, ..., Number10p0],
  maxDirectionFactor: [Number0p0, ..., Number10p0],
  spatialInterpolationMethod: 'String'
}

Hawaii (HI)

{
  modelVersion: 'v5.0.x',
  pgadFloor: Number,
  pgadPercentileFactor: Number,
  sadFloor: [Number0p0, ..., Number10p0],
  sadPercentileFactor: [Number0p0, ..., Number10p0],
  maxDirectionFactor: [Number0p0, ..., Number10p0],
  spatialInterpolationMethod: 'String'
}

Puerto Rico (PRVI)

{
  modelVersion: 'v5.0.x',
  pgadFloor: Number,
  pgadPercentileFactor: Number,
  sadFloor: [Number0p0, ..., Number10p0],
  sadPercentileFactor: [Number0p0, ..., Number10p0],
  maxDirectionFactor: [Number0p0, ..., Number10p0],
  spatialInterpolationMethod: 'String'
}