Instead of using an `import_map.json` file to define the versions for
dependencies, they are now defined directly within the import. Since the
`import_map.json` file should not be used anymore and instead a
`deno.json` file per function should be used, we decided to define them
directly with the code. The overhead compared to a `deno.json` file per
function shouldn't be that large and it makes using functions in a
self-hosted setup easier.
This commit updates all used Deno modules to their latest version.
Since some of the used modules / functions were deprecated we had to
adjust our encrypt / descrypt functions and the generation of the source
and item ids, where we have to use a new md5 function.
