[NV-3039] Migrate from sparkpost SDK to direct API calls with Axios

[LetItRock]

What?

In the @novu/sparkpost package we would like to migrate from using the sparkpost SDK to have a code that directly calls to the provider APIs. Check the documentation about the API here: https://developers.sparkpost.com/api/

Why? (Context)

Due to an un-maintained SDK, we should move from the official SDK' to working directly with the provider's API spec.

Definition of Done

• the SDK package has been removed from the package.json file
• the current provider functionality works with the calls to their APIs using Axios
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[michaldziuba03]

@LetItRock can you assign me, I'm currently working on other issue regarding Sparkpost and I want to avoid git conflicts

[harshit-senpai]

Hey I would like to work on it

[sccalabr]

I would be willing to work on this

[djabarovgeorge]

Hey @michaldziuba03,
We assigned you please let us know if you won't have the time to work on this issue so we can assign it if needed.

[ayushshukla7777]

Hey @LetItRock @djabarovgeorge , Since no one is activly working on this issue, I would like to raise a PR.

[michaldziuba03]

@ayushshukla7777 it's active

I'm waiting for merge: #3736

[ayushshukla7777]

hey @michaldziuba03 , I though it was inactive, my bad. Since I already did this, I will just put it here. After that merge, it can be helpful.