Task IPFS: support JWT from environment

[cusma]

Problem

Currently, the algokit task ipfs command requires a Pinata API JWT as keyring input, so the command can not be used programmatically (e.g. with GH secrets).

Solution

Add a --from-env option to the algokit task ipfs login command that grabs the Pinata JWT from a standard environment variable (e.g. ALGOKIT_PINATA_JWT).

Pros and Cons

PROS: enable programmatic use of the algokit task ipfs commands.
CONS: none.

Dependencies

No new dependency must be introduced.

[robdmoore]

Nice! good idea.