Rename models.LRPStartAuction to LRPStart

* Rename related methods and fields for consistency

[#83638694]

Signed-off-by: Atul Kshirsagar <atul.kshirsagar@gmail.com>
Extract common auction data into AuctionRecord struct

* embed struct in LRPStartAuction and TaskAuction
* fix error message typo

[#83638694]

Signed-off-by: Atul Kshirsagar <atul.kshirsagar@gmail.com>