Make oracle-related data on-chain parameters

[RiccardoM]

Context

Currently there some things about the Band Protocol integration that are hard-coded inside the Desmos codebase. You can find such things here:

const (
	// OracleScriptID represents the oracle script to be called on Band Protocol
	OracleScriptID = 32

	OracleAskCount   = 10
	OracleMinCount   = 6
	OraclePrepareGas = 50_000
	OracleExecuteGas = 200_000

	FeePayer = "desmos-ibc-profiles"
)

var (
	FeeCoins = sdk.NewCoins(sdk.NewCoin("band", sdk.NewInt(0)))
)

All of these should be moved as on-chain parameters in order to allow the governance to change them if needed (eg. Band Protocol changes the denom name, or we change the oracle script to be used).

Implementation proposal

I propose to implement a new set of x/profiles parameters as follows:

// Params defines the x/profile parameters
type Params struct {
 ... 
 Oracle Oracle
}

// Oracle contains the parameters of the oracle to be used when verifying application links
type Oracle struct {
  ScriptID int64
  AskCount uint64
  PrepareGas uint64
  ExecuteGas uint64
  FeePayer string
  FeeAmount sdk.Coins
}