Re-levelization: move non-docs content, rename content→docs

For better URLs, the content folder has been renamed 'docs' and all
other files have been moved up a level. Also, non-docs images have been
moved to the static folder at the top level where they belong.

Many relative paths had to be fixed to make this work.

docs/concepts/accounts/decentralized-identifiers.md

@@ -76,4 +76,4 @@ To learn more about the core properties of a DID document, see: [Decentralized I
 - You can include any content in a DID document, but should limit it to verification methods and service points. Since DIDs on XRPL can be resolved by anyone, you shouldn't include any personal information.
 - IPFS allows anyone to store content on the nodes in a distributed network. A common misconception is that anyone can edit that content; however, the content-addressability of IPFS means any edited content will have a different address from the original. While any entity can copy a DID document anchored with an XRPL account's `DIDDocument` or `URI` fields, they can't change the document itself unless they control the private key that created the corresponding `DID` object.
 
-{% raw-partial file="/_snippets/common-links.md" /%}
+{% raw-partial file="/docs/_snippets/common-links.md" /%}