* use std::source_location instead of godawful macros in logging
* remove unused/absolutely haram af json logstream
* fix bug in android logger where it doesn't respect eLogNone
We were linking/loading it in different ways, one with cmake option
`USE_JELLOC` and the other, older version `WITH_JEMALLOC`. This removes
the latter (which was default OFF) and keeps the former (which was added
and has been default ON since 0.9.4 or so).
Also removes the `ifdef`ed JEMALLOC code in lokinet.cpp because we don't
need it; just linking to jemalloc is enough to get the malloc/free
replacements.
