openssl: conditionally disable engine section

openssl: conditionally disable engine section

Currently, the build option to enable/disable engine support isn't
reflected in the final '/etc/ssl/openssl.cnf' config. It assumes `engines`
is always enabled, producing an error whenever running any
commands in openssl util or programs that explicitly use settings
from '/etc/ssl/openssl.cnf'.

```
➤ openssl version
FATAL: Startup failure (dev note: apps_startup()) for openssl
307D1EA97F000000:error:12800067:lib(37):dlfcn_load:reason(103):crypto/dso/dso_dlfcn.c:118:filename(libengines.so):
Error loading shared library libengines.so: No such file or directory
307D1EA97F000000:error:12800067:lib(37):DSO_load:reason(103):crypto/dso/dso_lib.c:152:
307D1EA97F000000:error:0700006E:lib(14):module_load_dso:reason(110):crypto/conf/conf_mod.c:321:module=engines, path=engines
307D1EA97F000000:error:07000071:lib(14):module_run:reason(113):crypto/conf/conf_mod.c:266:module=engines
```

Build should check for the `CONFIG_OPENSSL_ENGINE` option, and comment out `engines`
if not explicitly enabled.

Example:
```
[openssl_init]
providers = provider_sect
```

After this change, openssl util works correctly.

```
➤ openssl version
OpenSSL 3.0.14 4 Jun 2024 (Library: OpenSSL 3.0.14 4 Jun 2024)
```

Signed-off-by: Sean Khan <datapronix@protonmail.com>
Link: https://github.com/openwrt/openwrt/pull/15661
Signed-off-by: Robert Marko <robimarko@gmail.com>