Node config builder

[glihm]

Problem

we have a main config struct that encapsulates bunch of other smaller configs. this config struct is then passed to the katana_node::build() method.

https://github.com/dojoengine/dojo/blob/884a7267ff60752962193595eec87b01c9aa563d/crates/katana/node/src/config/mod.rs#L16-L28

https://github.com/dojoengine/dojo/blob/884a7267ff60752962193595eec87b01c9aa563d/crates/katana/node/src/lib.rs#L157-L163

because there are many configurations, it can be quite a hassle to specify each one of them. especially when you only want to specify some of them and want to use the default values for the rest. for example, in the dojo-test-utils:

https://github.com/dojoengine/dojo/blob/884a7267ff60752962193595eec87b01c9aa563d/crates/dojo/test-utils/src/sequencer.rs#L114-L122

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it'd be nice to have a ConfigBuilder where you can set individual values using the builder pattern. the logic for the katana_node::build() can then be moved to ConfigBuilder::build() method.

(ported from dojoengine/dojo#2648)
(related PR dojoengine/dojo#2653)