Feature Request: Enable "Legacy" Providers for "Old Environments"

[teward]

With OpenSSL 3.0, a number of older algorithms for signatures or crypto on things like P12 files. This makes importing things a little problematic for things a-la P12 importing or certificate importing.

Because of this still being a case with pfSense due to PHP stupidity that Sense is working on, certificates are exported in a way that modern OpenSSL and integrations won't work with, unless we permit programmatically "Legacy" provider for the import to be available to XCA. This would allow 'older' cert packages to be imported still and used.

While we should not permit exporting on these old legacy things, we should still permit "import" for modernization, etc. especially for privkeys.