RPC: add connection infos and uptime to getInfo

[D-Stacks]

This closes #2012, at least from what is written in the title, perhaps a getStats is required in addition.

[codecov]

Codecov Report

Merging #2095 (7ccd90c) into dev (14b2bcb) will decrease coverage by 2.39%.
The diff coverage is 47.22%.

@@            Coverage Diff             @@
##              dev    #2095      +/-   ##
==========================================
- Coverage   61.60%   59.20%   -2.40%     
==========================================
  Files         627      679      +52     
  Lines       29502    32966    +3464     
==========================================
+ Hits        18176    19519    +1343     
- Misses       8751    10620    +1869     
- Partials     2575     2827     +252     

Impacted Files	Coverage Δ
app/app.go	0.00% <0.00%> (ø)
app/appmessage/error.go	0.00% <0.00%> (ø)
app/appmessage/message.go	71.42% <ø> (ø)
app/appmessage/p2p_msgrequestanticone.go	0.00% <0.00%> (ø)
..._msgrequestnextpruningpointanditsanticoneblocks.go	0.00% <0.00%> (ø)
app/appmessage/protocol.go	100.00% <ø> (ø)
app/appmessage/rpc_get_balances_by_addresses.go	0.00% <0.00%> (ø)
app/appmessage/rpc_get_mempool_entries.go	0.00% <0.00%> (ø)
app/appmessage/rpc_submit_block.go	83.33% <ø> (ø)
app/protocol/flowcontext/errors.go	26.66% <0.00%> (-13.34%)	⬇️
... and 288 more

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