age-plugin-tlock identities also contain the length of the encoded url

[AnomalRoil]

The current format definition doesn't seem to conform to what is done in practice:

tlock-rs/age-plugin-tlock/README.md

Lines 134 to 139 in 8f3b313

	```
	AGE-PLUGIN-TLOCK-<TYPE><IDENTITY>
	```
	* `<TYPE>` is 0 for `RAW` or 1 for `HTTP`. It provides flexibility on upgrading the identity between implementation and threat model,
	* `<IDENTITY>` is the bytes of the beacon signature corresponding to the round for `RAW`, and is an remote HTTP URL in case of `HTTP`,

doesn't says so, but actually bincode is adding the length of the string, prepended in front of the string:
https://github.com/bincode-org/bincode/blob/trunk/docs/spec.md#collections

As can be seen in this playground link:
https://go.dev/play/p/-CoBESeIQr3

I'm currently working on a Go version of the age-tlock plugin and I think it'd be great to have both implementation rely on the same encoding and formats. Do you want to specify that the length is encoded too or do you want to only have the raw string following the value 1 ?

[AnomalRoil]

Actually it's not only that: it seems the VarInt encoding that bincode is using is not what is usually understood as "varint".

Could we find a common ground with a more "normal" type of encoding for recipients and identities?