router: add callro methods based on node zone#391

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eugenepaniot wants to merge 4 commits intotarantool:masterfrom

eugenepaniot:add-zone-based-replica-lb

Commits on Jan 10, 2023

Add callro methods based on node zone
eugenepaniot
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Commits on Jan 17, 2023

Update comments
eugenepaniot
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Commits on Jan 22, 2023

Use strings as load-balancing algorithm identificator
eugenepaniot
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Commits on Feb 15, 2023

Update test/router/router.result add new funct
eugenepaniot
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