Pr 727 create oracle services data agregator

[netboz]

Description

• Add value aggregator in front of services providers

Fixes #727

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update ( configuration file changed )

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• From 3 mocked services, asserts the median is computed from the received values
• From 4 mocked services ( even number ) asserts the median from the 2 mean values is returned

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[tenmoves]

this pr fixes #727 and not 272 (typo)

[samuelmanzanera]

I did try the PR and I got this error:

[bchamagne]

I tried to block 1 of the 3 providers (coinmarketcap) and I get this result:

2023-01-05 13:29:05.633 [warning] Service : Archethic.OracleChain.Services.UCOPrice : Cannot fetch values from
                provider: Archethic.OracleChain.Services.UCOPrice.Providers.CoinMarketCap with reason : [failed_connect: [{:to_address, {'coinmarketcap.com', 80}}, {:inet, [:inet], :econnrefused}], failed_connect: [{:to_address, {'coinmarketcap.com', 80}}, {:inet, [:inet], :econnrefused}]].
2023-01-05 13:29:05.703 [warning] Service : Archethic.OracleChain.Services.UCOPrice : Unexpected answer while querying provider : {:ok, {false, Archethic.OracleChain.Services.UCOPrice.Providers.CoinMarketCap}}
{:ok, %{"eur" => 0.04285300000000001, "usd" => 0.04542245773793001}}

The price is really far from what's on the 2 other provider (coinpaprika and coingecko are at ~0.8)

When I log result from the UCOPrice module :

_result: %{
  "eur" => [0.08478673041826183, 0.08488114771271422, 0.08625688028498835,
   0.08266352536799974, 0.08570600000000002],
  "usd" => [0.08987052666466204, 0.08997060520215051, 0.09142882643806899,
   0.0876200146429952, 0.09084491547586002]
}
{:ok, %{"eur" => 0.04285300000000001, "usd" => 0.04542245773793001}}