Add configurable list to ignore files in server watch
Add configurable list to ignore files in server watch

The following inside `config.toml` will ignore files ending with `.foo` and `.boo`.

```
watchIgnoreFiles = [ "\\.foo$", "\\.boo$" ]
```

The above is is a list of Reqular Expressions, but note the escaping of the `\` to make TOML happy.

Fixes #1189

fedelibre/hugo,derekperkins/hugo,mdhender/hugo,tubo028/hugo,ffrizzo/hugo,sprig/hugo,sprig/hugo,melo/hugo,bramp/hugo,kujohn/hugo,jygastaud/hugo,fedelibre/hugo,tatsushid/hugo,ryanclarke/hugo,tischda/hugo,mdhender/hugo,badoet/hugo,bogem/hugo,tjyang/hugo,jygastaud/hugo,coderzh/hugo,bramp/hugo,digitalcraftsman/hugo,ifraixedes/hugo,vbatoufflet/hugo,Zenithar/hugo,gohugoio/hugo,mdhender/hugo,bogem/hugo,Zenithar/hugo,tubo028/hugo,fhergomez/hugo,mdhender/hugo,coderzh/hugo,fedelibre/hugo,anthonyfok/hugo,abourget/hugo,MarkDBlackwell/hugo,gohugoio/hugo,ryanclarke/hugo,MarkDBlackwell/hugo,mitchchn/hugo,ifraixedes/hugo,gohugoio/hugo,fedelibre/hugo,badoet/hugo,melo/hugo,halostatue/hugo,mayah/hugo,kujohn/hugo,derekperkins/hugo,tjyang/hugo,anthonyfok/hugo,tischda/hugo,vbatoufflet/hugo,halostatue/hugo,anthonyfok/hugo,fhergomez/hugo,mitchchn/hugo,ffrizzo/hugo,tatsushid/hugo,soundrussian/hugo,soundrussian/hugo,mayah/hugo,abourget/hugo,digitalcraftsman/hugo