lib-sieve: mime/foreverypart: Enforced loop nesting limit across includes.

src/lib-sieve/plugins/include/ext-include-common.c

src/lib-sieve/sieve-interpreter.c

src/lib-sieve/sieve-interpreter.h

src/lib-sieve/sieve.c

src/testsuite/testsuite-script.c

src/testsuite/testsuite.c

tests/extensions/mime/errors.svtest

tests/extensions/mime/errors/limits-include.sieve

tests/extensions/mime/included/include-loop-2.sieve

tests/extensions/mime/included/include-loop-3.sieve

tests/extensions/mime/included/include-loop-4.sieve

tests/extensions/mime/included/include-loop-5.sieve