feat: Txs To Shares Roundtrip (rollkit#889)

Adds ability to:
- Convert `TxWithISRs` to Shares
- Convert Shares to byte array (that will be posted on celestia)
- Convert above byte array back to Shares
- Convert Shares back to `TxWithISRs`
- Parse Out of Context Shares

Adds relevant roundtrip tests

Resolves rollkit#881
Resolves rollkit#934
Resolves rollkit#886
Resolves rollkit#925

Note: All shares are written and interpreted as compact shares so they
contain reserved bytes (see
https://celestiaorg.github.io/celestia-app/specs/data_structures.html#compact-share)

Related PR in `celestia-app`:
celestiaorg/celestia-app#1770

third_party/celestia-app/testfactory/txs.go

@@ -30,31 +30,3 @@ func GenerateRandomTxs(count, size int) types.Txs {
 	}
 	return txs
 }
-<<<<<<< HEAD
-
-// GetRandomSubSlice returns two integers representing a randomly sized range in the interval [0, size]
-func GetRandomSubSlice(size int) (start int, length int) {
-	length = mrand.Intn(size + 1)         //nolint:gosec
-	start = mrand.Intn(size - length + 1) //nolint:gosec
-	return start, length
-}
-
-// CheckSubArray returns whether subTxList is a subarray of txList
-func CheckSubArray(txList []types.Tx, subTxList []types.Tx) bool {
-	for i := 0; i <= len(txList)-len(subTxList); i++ {
-		j := 0
-		for j = 0; j < len(subTxList); j++ {
-			tx := txList[i+j]
-			subTx := subTxList[j]
-			if !bytes.Equal([]byte(tx), []byte(subTx)) {
-				break
-			}
-		}
-		if j == len(subTxList) {
-			return true
-		}
-	}
-	return false
-}
-=======
->>>>>>> d71f90e (chore: repo refactoring (#1217))