Borsh serialize all values written to storage

[sug0]

Currently, the raw bytes of some values in Namada (e.g. VP and TX wasm code) are written to storage instead of their borsh serialized byte array. This poses a challenge for the migration software in Namada, which checks the types of updated key:value pairs using their borsh deserializers.

We should encode all values in storage with borsh to fix these issues.

[cwgoes]

@yito88 could you take this on quickly?

[cwgoes]

@yito88 how long do you estimate is remaining here?

[yito88]

@cwgoes done

[yito88]

NOTE: Some IBC-related data are still not-borsh serialized because they should be proven for ICS-23