explorer/: Show detailed account history

[jstarry]

Problem

• Want to see details of recent account history
• The current UI is very opaque (only shows signature, slot, status)

Proposed Solution

• Show instructions rather than transactions
• Display program id and instruction name if possible
• Add filters to UI for whether account was a signer / writable in a tx / ix
• Show pending transaction instructions

Blocked on RPC support:

• getConfirmedTransaction is not batchable
• getConfirmedTransaction is not filterable
• getConfirmedTransaction does not return pending info