Proposal of a roadmap towards a v1 release

[jenkin]

No fundamental changes in draft spec.

• rename draft folder to v1
• update revision from 0.1 to 1.0
• fix copyright notice (CC0 is public domain, not attribution)
• remove all default: null (optional attributes can be simply omitted)
• add examples for all attributes (ie. no "district": null)
• remove all TODO notices
• refactor spec text taking inspiration from RFC7946 (GeoJSON spec)
• build an index.html file from spec md file (served as homepage, ie. using markdown-to-html-cli)
• add JSON Schema with checksum Proposal of an official JSON Schema for geocodejson #24
• build an interactive page to navigate spec schema (ie. using @stoplight/json-schema-viewer)
• enable github pages to serve static content
• add a changelog
• add a code of conduct
• add contributing guidelines
• add a LICENSE file
• enrich README in root folder
• define issue templates: proposal, bug, q&a, use case report
• close all open issues