Proto/gas: update gas for K

Context

Fix #3309 (closed)

This MR contains changes to the gas for the protocol K. Reports are available at https://gitlab.com/lrand/gas-reports/-/tree/master/K

The changes are quite minimal this time around. Most notably, I don't believe any new costs were included in this protocol (and if there were, I couldn't find the issue related to them). If you feel something is missing, don't hesitate to point it out. The following table contains the list of changes

Name	Kind	Old	New	Diff	Diff (%)
cache_update_coeff	coeff	57	43	-14	-24.56%
N_IDupN	coeff	1.125	1.25	+0.125	+11.11%
ENCODING_Chest_key	const	13500	10000	-3500	-25.93%
ENCODING_Chest	const	16630	12200	-4430	-26.64%
TIMESTAMP_READABLE_DECODING	const	800	105	-695	-86.87%
TIMESTAMP_READABLE_DECODING	coeff	0.375	0.0469	*2^-3	-87.5%
TIMESTAMP_READABLE_ENCODING	const	100	820	+720	+720%
collect_tickets_step	coeff	60	80	+20	+33.33%
N_IEmit	const		30
Inbox_add_message (tx_rollup)	coeff		445
Commitment_full_compact (tx_rollup)	coeff		915
Verify_proof_proof_size (tx_rollup)	coeff		124
Verify_proof_message_size (tx_rollup)	coeff		8416

I believe the timestamp encoding constants have been mixed up at some point in a previous protocol gas patch, which is why the changes are so drastic. I don't have good reasons for the other changes. Pinging @MarcBeunardeau for the chest changes, @yrg for the cache changes, and @lthms for tx_rollup changes.

Gas diff: gas-diff

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR