fb434159d1 Remove global symbols: Avoid using the global namespace if possible (practicalswift)
Pull request description:
Remove global symbols: Avoid using the global namespace if possible.
Partially resolves #15612 ("Reduce the number of global symbols used").
Change in global symbols as reported by `nm bitcoind` before vs after:
```
$ diff -u <(nm src/bitcoind-before | c++filt | grep -E '^[0-9a-f]+ [A-Z] ' | cut -f3- -d' ' | sort -u) \
<(nm src/bitcoind-after | c++filt | grep -E '^[0-9a-f]+ [A-Z] ' | cut -f3- -d' ' | sort -u) \
| grep -E '^[+-][^+-]'
-boundSockets
-cs_warnings
-eventHTTP
-fFeeEstimatesInitialized
-fLargeWorkForkFound
-fLargeWorkInvalidChainFound
-pathHandlers
-strMiscWarning[abi:cxx11]
-threadHTTP
```
ACKs for commit fb4341:
Tree-SHA512: d2f78f6188a992b0e0de8d107e2c494cfa0faa2de4fda634a1d3606d6515633bec86289cf2a2e78ffe467b17b795e2243cc459fb44e0dfe2fc69899506ff61c9
Backport of Core PR15622