Implement pallet_registrar hooks

[tmpolaczyk]

Allows to execute code on container chain register and deregister. This PR only includes the deregister hooks:

• Clear Registrar storage: BootNodes and ParaGenesisData, and return parachain deposit (this used to be done immediately, now it will be done after 2 sessions)
• Call AuthorNoting::kill_author_data
• Call ServicesPayment::set_credits(0)

These hooks are executed 2 sessions after calling deregister, which is when the container chain won't have any collators anymore. Unless the para id was never marked as valid_for_collating, in that case the hooks are executed immediately.

Also, change the pausing mechanism. Add a new extrinsic to unpause: unpause_container_chain. Previously mark_valid_as_collating was used to unpause, now that won't work anymore. This change was needed because otherwise pausing and unpausing could trigger the implemented hooks when it should not, so now paused container chains are stored in a new storage item Paused instead of being in PendingVerification. Container chains that were paused before this PR will need to be unpaused using mark_valid_for_collating.

[github-actions]

Coverage Report

(master)

@@                    Coverage Diff                     @@
##           master   tomasz-registrar-hooks      +/-   ##
==========================================================
+ Coverage   71.37%                   71.39%   +0.02%     
+ Files          86                       89       +3     
+ Lines       19709                    19791      +82     
==========================================================
+ Hits        14067                    14128      +61     
+ Misses       5642                     5663      +21     

Files Changed	Coverage
/container-chains/templates/frontier/node/src/chain_spec.rs	71.74% (-3.02%)	🔽
/container-chains/templates/frontier/node/src/command.rs	20.59% (-0.12%)	🔽
/container-chains/templates/frontier/node/src/service.rs	76.77% (-1.18%)	🔽
/node/src/command.rs	15.51% (-0.06%)	🔽
/node/src/service.rs	17.72% (-14.28%)	🔽
/pallets/registrar/src/lib.rs	92.68% (-1.71%)	🔽
/runtime/dancebox/src/lib.rs	79.48% (-0.27%)	🔽

Coverage generated Fri Nov 24 17:37:58 UTC 2023

[girazoki]

Ideally I would like to see tests that capture the following cases:

• a parachain is pending to be a registered para and we deregister it. In this case we should not call the hook immediately
• a prachain is pending to be paused and we deregister it. In this case, we should not call the hook immediately

[tmpolaczyk]

Suggested change

	fn integrity_test() {
	fn try_state(_block_number: u32) {

The integrity_test hook doesn't have access to the storage, despite docs saying otherwise.

[fgamundi]

LGTM