Fixed the OTX provider due do API path confusion

[BastienFaure]

Hey !

First, thank you for this tool, I used it a lot during engagement and find it very handy :)

I realized no later than today that myself and one of my coworkers had different outputs but targeting the same hostname (subdomain.domain.com).

Intercepting the gau requests and reading a bit about the OTX documentation made me realize that the API endpoint currently used in the OTX provider would return data only when a domain is provided, but nothing when a subdomain is provided (https://otx.alienvault.com/assets/static/external_api.html)

I just made a couple of changes to make sure the right endpoint is used depending on the input (domain or subdomain) and also made sure that the -subs switch would still work. If you feed the x.y.z hostname to gau without the -subs switch, the OTX provider will use /api/v1/indicators/hostname/{hostname}/{section} as this endpoint returns URL for a hostname that is not a domain. Now if you want the subdomains of that hostname (e.g. a.x.y.z and b.x.y.z), it will use the /api/v1/indicators/domain/{domain}/{section} and for every key in the return dict, check if it contains the submitted hostname.

I didn't include the go.mod and the go.sum as I don't know your opinion about versioning but feel free to add them if you feel the PR useful and you're into reproductible builds :)

[lc]

Hey @BastienFaure,

Thanks for opening this PR! I'm currently busy this week with final exams, but I will review this as soon as I can.

[lc]

Looks good, thanks!