Improve tooltip descriptions for `RefTime` and `ProofSize`

[cmichi]

We have info-tooltips here:

The "RefTime Limit" tooltip currently says:

The maximum amount of gas to use for execution (the old gas limit). If the transaction requires more, it will fail.

The issue here is that the user typically won't know what "gas" means here, and also not what "old gas" means.

For "ProofSize Limit":

The maximum amount of gas to use for PoV. If the transaction requires more, it will fail.

The issue here is that the user typically won't know what PoV refers to, I would formulate it like below.

I suggest for "RefTime Limit"

The amount of computational time used for execution. If the transaction requires more, it will fail.

For the "ProofSize Limit" tooltip I suggest:

The amount of storage space used, in bytes. If the transaction requires more, it will fail.

I would avoid introducing the term "weight" here and use the more general "amount".

[statictype]

Sounds good @cmichi!
I suggest keeping "maximum" around since we are talking about the limits not the values themselves.

The maximum amount of computational time that can be used for execution, in picoseconds
The maximum amount of storage space that can be used, in bytes.