Murisi/masp separate parallel sync rebased

[murisi]

Describe your changes

This PR creates a separate synchronization command and heavily draws code from #2422 . More specifically, this PR's changes are as follows:

• Parallelized the downloading of transactions with the scanning of transactions and updating of the note Merkle tree
  • This reduces the wall-clock time required to synchronize the shielded context
  • This allows us to avoid having to cache downloaded transactions until transaction scanning starts
• Created a separate command to synchronize the shielded context called shielded-sync
• Adjusted all other commands to no longer implicitly synchronize the shielded pool before executing their actions
• Modified the synchronization function to save state frequently so that the interrupted and resumed without data loss
• Adjusted the integration tests so that they now explicitly do shielded-syncs before doing any actions

Indicate on which release or other PRs this topic is based on

Namada v0.30.3

Checklist before merging to draft

• I have added a changelog
• Git history is in acceptable state

[brentstone]

Is this still relevant? @batconjurer @grarco

[batconjurer]

Is this still relevant? @batconjurer @grarco

No