feat: add endpoint to trigger sending of verification email

[wa0x6e]

Add an endpoint to trigger the verification email sending again.

endpoint: POST /, with wallet address in the body. Will send a verification email again to the pending email address associated to this wallet in the DB.

In case there is more that 1 email, use the last one. (most recently added)

TBD: Whether to also require a wallet signature for this request. Also, have a mechanism to prevent spamming of this feature