As per the discussion in PR #18047, split the MTR package into
two, one with jansson enabled for JSON output, and one without.

This commit also bumps the version to 0.95. Since the MTR project
website does not seem to be updated with builds any longer, switch
to GitHub Codeload instead.

Also enable PKG_FIXUP:=autoreconf so that MTRs bootstrap.sh process
is executed properly.

Signed-off-by: Marc Egerton <marc@malloc.me>