Adding ability to disable src cache

[arunes]

Adding ability to disable src cache based on the #123

You can set the disable cache from the root config, it will work for all custom image avatars.

AvatarModule.forRoot({
  colors: avatarColors,
  disableSrcCache: true
})

It will add Math.random() to end of the image urls when set to true.

Added new tests

[Heatmanofurioso]

Hi @arunes
Would you mind if I took this change to my ported version of the library? Since the owner doesn't seem to be maintaining it anymore, I'm trying to maintain and keep up to date my own version of this library

[arunes]

Hi @arunes Would you mind if I took this change to my ported version of the library? Since the owner doesn't seem to be maintaining it anymore, I'm trying to maintain and keep up to date my own version of this library

Sure go ahead!