Adds: Strategy docs and standards

.github/workflows/deploy.yml

content/PlanetarySDIs/about.md

content/europa/_index.md

content/europa/data/data_products.md

content/europa/data/data_services.md

content/europa/get_involved.md

content/europa/governance/_index.md

content/europa/governance/charter.md

content/europa/roadmap.md

content/europa/standards/cartographic_standards.md

content/europa/standards/data_formats.md

content/europa/standards/data_standards.md

content/europa/standards/metadata_standards.md

content/europa/standards/spatial_standards.md

content/europa/strategy/_index.md

content/europa/strategy/roadmap.md

content/europa/strategy/strategy.md