Merge branch 'restructure-sidebar' into 'main'

docs/changelog.md

docs/details/callbacks.mdx

docs/details/pgp-export.md

docs/getting-started/account.mdx

docs/getting-started/authentication.mdx

docs/getting-started/event-log.mdx

docs/getting-started/first-steps.mdx

docs/getting-started/metadata.md

docs/getting-started/schema-validation.mdx

docs/getting-started/submission/data.mdx

docs/getting-started/submission/metadata.mdx

docs/getting-started/submission/structure.mdx

docs/glossary.md

docs/metadata/additionalReferenceInfo.mdx

docs/metadata/authenticationInformation.mdx

docs/metadata/contentStructure.mdx

docs/metadata/overview.mdx

docs/metadata/paymentInformation.mdx

docs/metadata/publicServiceType.mdx

docs/metadata/replyChannel.mdx