Post things here that need explicit mention in 0.13 release notes

I'd strongly prefer for pulls to just update doc/release-notes.md directly, but if they somehow slip by, mention them here.

Summary:

• New options:
  • -maxtimeadjustment: P2P: add maxtimeadjustment command line option #7573
  • -reindex-chainstate ( Optimize reindex Optimize reindex #7917 ) (done in [0.13] Document reindexing changes #8465)
• New RPC call:
  • generatetoaddress: [RPC] Add generatetoaddress rpc to mine to an address #7671
  • importprunedfunds removeprunedfunds: [RPC] Add import/removeprunedfunds rpc call #7558
  • signmessagewithprivkey (introduced in Create signmessagewithprivkey rpc #7953)
• Removed RPC calls:
  • setgenerate Removal of internal miner: Make the generate RPC call function for non-regtest #7663, Remove internal miner #7507
• Changed RPC calls
  • Output of RPC call getrawmempool has changed sort order (Several performance and privacy improvements to inv/mempool handling #7840)
  • fundrawtransaction: Add multiple options to fundrawtransaction #7518 Add multiple options to fundrawtransaction
  • fundrawtransaction: [RPC] add feerate option to fundrawtransaction #7967/ [rpc] fundrawtransaction feeRate: Use BTC/kB  #8153 add feerate option to fundrawtransaction
• ARM executables have been added in Add armhf/aarch64 gitian builds #8188: need to update the release notes, as well as possibly the release process Mention Linux ARM executables in release process and notes #8233
• disabled mempool command when remove NODE_BLOOM support
• End support for Windows XP and older End support for Windows XP and older #7681