* feat: initial goroutine blob submission implementation

test(batcher): add e2e test for concurrent altda requests

doc: add explanation comment for FakeDAServer

chore: fix if condition in altda sendTransaction path

feat: add maxConcurrentDaRequests config flag + semaphore

refactor: batcher to use errgroup for da instead of separate semaphore/waitgroup

fix: nil pointer bug after using wrong function after rebase

fix: defn of maxConcurrentDaRequests=0

fix: TestBatcherConcurrentAltDARequests

chore: remove unneeded if statement around time.Sleep

refactor: use TryGo instead of Go to make logic local and easier to read

chore: clean up some comments in batcher

chore: make batcher shutdown cancel pending altda requests by using shutdownCtx instead of killCtx

* chore(batcher): make altda wg wait + log only when useAltDa is true

* refactor: batcher altda submission code into its own function

* test: refactor batcher e2e test to only count batcher txs

* chore: log errors from wait functions

* chore: refactor and minimize time that e2e batcher system tests can run

* chore: lower timeout duration in test

* fix(batcher): maxConcurentDARequests was not being initialized