Make torrequest optional

[ppfeister]

Closes #2130

Sample interaction without dependency:

$ sherlock --tor test
Using Tor to make requests
Warning: some websites might refuse connecting over Tor, so note that using this option might increase connection errors.
[*] Checking username test on:

Important!
> Dependencies for --tor and --unique-tor are now optional, and WILL BE DEPRECATED in a future release of Sherlock.
> If you've installed Sherlock via pipx, you can install the dependency with `pipx install sherlock-project[tor]`.
> Other packages should refer to their packager maintainer's documentation, or install separately with `pipx install torrequest`.

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[ppfeister]

Not 100% on this one, may need another look

[sdushantha]

Looks good to me. I doubt many people will notice this as I doubt may use --tor, but that's just an assumption