consider replacing `#` commands with "dedicated micro web app(s)"

currently there are Find `#` commands, such as:
- `#add ` and `#del `
- `#import ` and `#export` to JSON
- `#help` half working help, making a query to find with the user; used as example

All these functions, are provided with the `Find` instance as first argument, and the user query (without the command) as second arg.

These `commands` are defined under the `#` symbol, and instead of being under the key `.engines` like other symbols, these commands/functions are defined under the `.fns` key of the js symbol map.

It is practical as a semantic to demonstrate the separation of meaning, and "execution type", between symbols.

Maybe these functions, could be replaced, by an other already existing symbol, for example:
```txt
+find-add-engine-for-symbol
+find-add
+fadd (a sym)
;; or any semantic; ++add could work too (symbol + engine +add )
```

This could build the URL(s), for destination of the "internal Find client", with a different query param: `f` for `find`, `s` for `settings`, or with a different "user query value than the initial"; `i4k-find://` for find "URI building scheme", or `i4k-find:` to match protocol syntax.
```txt
https://example.org/find-instance/#f=
https://example.org/find-instance/#q=i4k-find:[,//]//
https://example.org/find-instance/#q=i4k-find:?:?:
```

There are interesting examples https://en.wikipedia.org/wiki/List_of_URI_schemes om how to make "list of ressources", contact, notes, tags, fm, dns, etc. with various patterns, maybe to nest and chain queries/commands.

That way the functions/commands could be moved together with the rest and follow the classic engine(s) behavior (or opening a new URL with the user query into the URL patterns, and let the app handle how to interpret what to do with it)