Old, EoL OpenSSL library (1.1.1s) used in latest MeshAgent

[mwllgr]

Hello,

the bundled OpenSSL library hasn't been updated in a while (two years!), last update was in commit 9d38b7e.
The currently used version seems to be 1.1.1s which is EoL since one year now: https://www.openssl.org/blog/blog/2023/03/28/1.1.1-EOL/index.html

OpenSSL 1.1.1 was released on 11th September 2018, and so it will be considered EOL on 11th September 2023. It will no longer be receiving publicly available security fixes after that date.

I don't think that it's too hard to update the libraries stored in the openssl/ subfolder, but I am in no means experienced in C, but I think it's really important that we update libraries like these as I already mentioned at #214. Just thought that it'd be better to open a separate issue for the OpenSSL library.