We had one user with EDMC trying to send: ```python OrderedDict([('$schemaRef', 'https://eddn.edcd.io/schemas/codexentry/1'), ('message', OrderedDict([('timestamp', '2021-10-26T11:37:57Z'), ('event', 'CodexEntry'), ('EntryID', 2420702), ('Name', '$Codex_Ent_Stratum_07_K_Name;'), ('SubCategory', '$Codex_SubCategory_Organic_Structures;'), ('Category', '$Codex_Category_Biology;'), ('Region', '$Codex_RegionName_18;'), ('System', 'Xi Ophiuchi'), ('SystemAddress', 2072061675891), ('NearestDestination', ''), ('Latitude', 79.352364), ('Longitude', 121.434044), ('horizons', True), ('odyssey', True), ('StarPos', [-3.875, 8.15625, 55.875]), ('BodyName', 'Xi Ophiuchi B 5'), ('BodyID', 14)]))]) ``` as the message. The EDDN Gateway then complains: `FAIL: [<ValidationError: "'' is too short">]`
* Add BodyID and BodyName as optional keys. * Add `description` at top-level pointing to README documentation. * Add schema-specific README to document what should be (in|ex)cluded from data, and how to obtain such from Journals etc.
