expose unique hostnames functionality (-dns flag) in library

[tarunKoyalwar]

tlsx version:

main

Proposed Changes

• unique hostnames from SAN , CN introduced in add dns flag #350 in added in runner package https://github.com/projectdiscovery/tlsx/pull/350/files which is limited to cli and hence not exposed in library mode
• as seen in example https://github.com/projectdiscovery/tlsx/blob/main/examples/simple.go . we use tlsx package in library mode
• move / implement logic in tlsx package especially in 'service' struct . to expose it in library
• consider renaming hostname json variable, sincenuclei already has Hostname field ( cc: @ehsandeep )

// nuclei -svd
Hostname => google.com:443
// tlsx -dns -json
"hostname": [ "google.co.in" ]

may be we can use domains/hosts etc

Anything else: