Add in-node RPC cache, optimize getloaninfo, refactor getburninfo

[prasannavl]

/kind feature

• Adds support for rpccache=0/1/2 defaulting to 1 - all.
• Auto cache one block height of data of each RPC call for each parameter set for common non-wallet get/list RPCs. Node being re-queried for data per block that doesn't change is being observed as a common pattern, esp, across heavy users like Ocean infrastructure. While these are better optimized with infrastructure level cache, a thin optional node level caches, does help with requests that do hit the node. Particularly, since the cache by-passes the chain state locks entirely.
• In addition, also remove BlockUntilSyncedToCurrentChain() on some of the list APIs, where this is not strictly necessary.
• Rewrite of getloaninfo to optimize it for parallel cores.
• Refactors getburninfo.