Provide more options for startTls

[shiyuhang0]

StartTlsOptions only provide limited options for us.

deno/ext/net/lib.deno_net.d.ts

Line 269 in da23f7f

export interface StartTlsOptions {

Is there any plan to add more options? example:https://dev.mysql.com/doc/refman/8.0/en/using-encrypted-connections.html

I think there are some thing important:

• something like ssl-mode to support fallback to non-tls and skip ca verify
• something like tls-version to choose the version of tls