Embed schema.json into binary to ease distribution

[kpbaks]

I am trying to add support for the lsp in helix. Here users need to install the lsp on there own, so having the server be more than only the binary file makes this experience poor, since they would have to install the binary and the schema.json, and then change their config to override how the lsp command is defined to point at their copy of the file using -schema <my-path>/schema.json.

This could be improved and simplified by distributing schema.json file embedded into the binary using A go:embed directive.