feat: max touches/min touches functionality should be added to the gesture utility

# Bug Report

**Ionic version:**

[x] **5.x**

**Current behavior:**
When navigating back using the swipeback gesture, it is possible to let the previous page jump and flicker by adding additional (multi touch) input using other fingers.

In practice, this happens accidentally when another part of the same or another hand covers the susceptible area (the previous page), resulting unwanted nav actions.

I don't even know whether this counts a bug, it's just a thing users have noticed and which feels a little bit off compared to the swipeback behaviour on iOS.

**Expected behavior:**
The page transition should be unaffected by additional touch input.

**Steps to reproduce:**
--> In an Ionic Angular App:
- Navigate to any page allowing you to either go- or swipe back
- Initiate a swipeback transition and add additional (multi touch) input to the leaving page

**Related code:**

None.

**Other information:**


**Ionic info:**

```
Ionic:

Ionic CLI : 6.6.0 (/Users/xxx/.nvm/versions/node/v10.16.3/lib/node_modules/@ionic/cli)
Ionic Framework : @ionic/angular 5.0.7
@angular-devkit/build-angular : 0.803.26
@angular-devkit/schematics : 8.3.26
@angular/cli : 8.3.26
@ionic/angular-toolkit : 2.2.0

Cordova:

Cordova CLI : 9.0.0 (cordova-lib@9.0.1)
Cordova Platforms : ios 5.1.1
Cordova Plugins : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview 4.2.0, (and 4 other plugins)

Utility:

cordova-res (update available: 0.13.0) : 0.8.1
native-run : 1.0.0

System:

ios-deploy : 1.10.0
ios-sim : 8.0.2
NodeJS : v10.16.3 (/Users/xxx/.nvm/versions/node/v10.16.3/bin/node)
npm : 6.9.0
OS : macOS Catalina
Xcode : Xcode 11.4.1 Build version 11E503a
```

Start by locating the gesture utility that handles the swipeback transition and inspect how it processes additional touch input. Reproduce the multi-touch swipeback case described in the issue, then verify that extra touches no longer alter or flicker the page transition.

索引モデルが issue の本文から書いたものです。