feat(library/kernel_bindings): expose import/export functions in the Lua API

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/module): add extra function for adding uncertified declarations when trust_lvl > LEAN_BELIEVER_TRUST_LEVEL

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/kernel_bindings): declarations added with the function add_decl are automatically registered in the to-export list

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(library/module): bug in export_module procedure

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(library/kernel_serializer): bug in declaration serialization

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(library/module): bug in next_task method

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
fix(kernel/environment): bug in extension id checking

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
test(lua): add Acc datatype declaration test

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
test(lua): add simple module export/import test

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>