Activate UniswapV3 pool fetching periodic maintenance

[sunce86]

This PR activates periodic background maintenance task to update the pools liquidity on UniswapV3 pools (I forgot to add this in #388).

Initially, this was intended to be done with:
uniswap_v3_pool_fetcher.spawn_maintenance_task(...)
but it makes more sense to me to add this function to the ServiceMaintenance which is triggered on each new block. Although currently UniswapV3 is using subgraph under the hood, this change makes even more sense since we are moving towards an event based pool liquidity update.

[nlordell]

LGTM

[codecov-commenter]

Codecov Report

Merging #427 (4ca1b20) into main (1e5aa9e) will increase coverage by 0.04%.
The diff coverage is 0.00%.

❗ Current head 4ca1b20 differs from pull request most recent head f118b82. Consider uploading reports for the commit f118b82 to get more accurate results

@@            Coverage Diff             @@
##             main     #427      +/-   ##
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+ Coverage   64.32%   64.37%   +0.04%     
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  Files         227      227              
  Lines       43450    43425      -25     
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+ Hits        27950    27953       +3     
+ Misses      15500    15472      -28