General clean up needed to remove Oasis Scan v1

[buberdds]

General clean up needed to remove Oasis Scan v1

• remove/update api-transaction-methods.cy.ts E2E tests clean up #2101
• vendor removal, clean up settings.json, gitattributes Remove Oasis Scan v1 API #2105
• dump validators Switch dump validators to Nexus #2102
• update e2e route E2E tests clean up #2101
• update readme (add nexus info) Include Nexus in readme #2100
• From @lukaw3d Update new Oasis Scan API urls docs#1051 Update Oasis Scan API urls sapphire-paratime#473

https://github.com/search?q=org%3Aoasisprotocol+https%3A%2F%2Fapi.oasisscan.com%2Fmainnet%2Fv2&type=code
https://api.oasisscan.com/mainnet/v2 ->
https://api.oasisscan.com/v2/mainnet

https://github.com/search?q=org%3Aoasisprotocol+https%3A%2F%2Fapi.oasisscan.com%2Fmainnet%2Fswagger-ui%2F&type=code
https://api.oasisscan.com/mainnet/swagger-ui/#/runtime-controller ->
https://api.oasisscan.com/v2/swagger/#/runtime