Extract TAP-based tests for box from app/ to box-tap/

test/box-tap/cfg.result

test/box-tap/cfg.test.lua

test/box-tap/cfgup.result

test/box-tap/cfgup.test.lua

test/box-tap/net.box.result

test/box-tap/net.box.test.lua

test/box-tap/session.result

test/box-tap/session.test.lua

test/box-tap/suite.ini

test/box-tap/trigger_atexit.result

test/box-tap/trigger_atexit.test.lua

test/box-tap/trigger_yield.result

test/box-tap/trigger_yield.test.lua