Use the new conventions on `user_identity` for SOLO mining with SRI Pool

[GitGab19]

After stratum-mining/sv2-apps#321 is merged, we need to modify the wizard embedded in the UI on #17 to configure the user_identity used by tProxy accordingly.

[pavlenex]

@GitGab19 Did we implement this now?

[GitGab19]

Not yet, because I wanted to wait for stratum-mining/sv2-apps#321 to be merged before doing that.