Add support for manual SSL certs/keys

[mattdodge]

This is the work done to address #511 that I created a while back.

Essentially, it adds two optional CLI args for providing a path to an SSL cert and private key. This allows you to create certs using another tool such as mkcert and use them in serve.

Here is a possible workflow:

$ mkcert -install
Using the local CA at "/Users/matt/Library/Application Support/mkcert" ✨
The local CA is now installed in the Firefox trust store (requires browser restart)! 🦊

$ mkcert localhost
Using the local CA at "/Users/matt/Library/Application Support/mkcert" ✨
Created a new certificate valid for the following names 📜
 - "localhost"
The certificate is at "./localhost.pem" and the key at "./localhost-key.pem" ✅

$ serve --ssl-cert ./localhost.pem --ssl-key ./localhost-key.pem

   ┌────────────────────────────────────────────────────┐
   │                                                    │
   │   Serving!                                         │
   │                                                    │
   │   - Local:            https://localhost:5000       │
   │   - On Your Network:  https://192.168.0.126:5000   │
   │                                                    │
   │   Copied local address to clipboard!               │
   │                                                    │
   └────────────────────────────────────────────────────┘

This does not do any kind of cert creation, cert validation, or automatic HTTPS - it just lets you serve with HTTPS if you happen to have certs already.

[joeySchentrup]

I like this a lot. Adding this functionality will assist a lot of people.

[dogancana]

Any update on this? Looks ready to me :)

[IKS-Ploetzwich]

This is really needed. Please review and implement.

[leo]

Thank you so much! This looks great.

In most cases, of course, your production environment (proxy) should be taking care of terminating the SSL setup. I do understand, however, that this can still be useful for cases where there's no proxy or for local development.

[leo]

Out now!

[lacivert]

I believe this needs a simple note on documentation. I could find the usage agruments on cli but there is no docs on markdown pages

[Alexufo]

must be in readme