impr: delphioracle upsert

[AndlerRL]

Changelog:

• Added SQL upsert row length guard for error prone.
• Improved the mapping and filtering of the delphioracles contract with their datapoints table, to limit the amount of updates per new block received.
• Updated eosio + wharftkit dependencies.
• Fixed the row upsert duplication. Now each row should be unique.
• Improved row uniqueness (part of the fixed above).

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TODO:

• Limit even further the delphioracle updates: Use the declared env vars to set up a verification of new rows if they are worth to update or not for every XX minutes, declared as the value of this env var.
• Improve some conditionals: At code level, there are some conditions that are redundant like for example row.length === 0... It is better and easier to read the !row.length

[AndlerRL]

My ETA for this one (for the TODO items) is tonight at my EOD. I noticed that there is a few to be done before to push it to master and prior to update the indexer on the related VM.

cc - @gaboesquivel