Add linter checks to GHA & Fix code to pass lints

Add linter checks to GHA & Fix code to pass lints.
The linters added are:
- whitespace: Tool for detection of leading and trailing whitespace
- gosec: Inspects source code for security problems
- gci: Gci control golang package import order and make it always deterministic
- misspell: Finds commonly misspelled English words in comments
- gomnd: An analyzer to detect magic numbers

The file utils/utils.go is excluded from the checks of gomnd, as uses magic numbers through the code

coordinator/coordinator.go

@@ -294,17 +294,14 @@ func (c *Coordinator) isForgeSequence() bool {
 }
 
 func (c *Coordinator) purgeRemoveByTimeout() error {
-
 	return nil
 }
 
 func (c *Coordinator) purgeInvalidDueToL2TxsSelection(l2Txs []*common.PoolL2Tx) error {
-
 	return nil
 }
 
 func (c *Coordinator) shouldL1L2Batch() bool {
-
 	return false
 }