feat: Increase sync blocks requested and make it configurable

[ecp88]

• Right now we send a max of 5 block requests when syncing. This is insufficient for archival nodes to catchup to the tip of the network.
• This change makes the default 10 (from 5) and makes it a config param in the client config to allow node operators to tweak this param.
• Using 10 as default allows archival nodes to be able to catch up. We have used this code change in Pagoda for allowing archival nodes that have fallen behind to catchup to the tip.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 96.77419% with 1 line in your changes missing coverage. Please review.

Project coverage is 71.81%. Comparing base (229d287) to head (806213d).

Files	Patch %	Lines
chain/client/src/sync/block.rs	95.83%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #11820 +/- ## ========================================== + Coverage 71.80% 71.81% +0.01% ========================================== Files 796 796 Lines 163200 163211 +11 Branches 163200 163211 +11 ========================================== + Hits 117182 117217 +35 + Misses 40973 40947 -26 - Partials 5045 5047 +2 ``` | [Flag](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | Coverage Δ | | |---|---|---| | [backward-compatibility](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `0.23% <0.00%> (-0.01%)` | :arrow_down: | | [db-migration](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `0.23% <0.00%> (-0.01%)` | :arrow_down: | | [genesis-check](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `1.35% <33.33%> (+<0.01%)` | :arrow_up: | | [integration-tests](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `37.81% <32.25%> (+0.06%)` | :arrow_up: | | [linux](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `71.56% <96.77%> (+0.01%)` | :arrow_up: | | [linux-nightly](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `71.40% <96.77%> (+<0.01%)` | :arrow_up: | | [macos](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `54.69% <96.77%> (+1.61%)` | :arrow_up: | | [pytests](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `1.62% <33.33%> (+<0.01%)` | :arrow_up: | | [sanity-checks](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `1.42% <33.33%> (+<0.01%)` | :arrow_up: | | [unittests](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `66.27% <96.77%> (+0.01%)` | :arrow_up: | | [upgradability](https://app.codecov.io/gh/near/nearcore/pull/11820/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near) | `0.28% <0.00%> (-0.01%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=near#carryforward-flags-in-the-pull-request-comment) to find out more.

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