core: add setting error injections via env

Sometimes, it's useful to set error injections via environment
variables and this commit adds this opportunity.

e.g: `ERRINJ_WAL_WRITE=true tarantool` will be launched with
ERRINJ_WAL_WRITE setted to true.

Errinjs with bool parameters can be set to "true", "false",
"True", "False", "TRUE", "FALSE", etc. (case-insensitive variable).

Errinjs with int or double parameters should be whole valid ("123s" is invalid).
e.g. for int or double: "123", "-1", "2.34", "+2.34".

NOTE: errinjs should work only in debug mode, so added `release_disabled` in
suite.ini. But there is a bug in test-run: `release_disable` disables tests at
each build type. Partially this problem is descripted in tarantool/test-run#199.

Part of #5040