update to terser v5
replace gulp-remove-code with a rough equivalent in the gulpscript itself
replace gulp-inline with gulp-inline-source-html
remove base64 modules as redundant when running inline-source (does both)
remove crass as redundant when running inline-source (uses csso)
fixup jquery source map comment (but still keep the actual file)

at least now this seems stable enough to start more of the ui tweaking

pure-css 1.0.0 -> 2.0.3
datatable 1.10.16 -> 1.10.23
generic jquery-slim -> custom jquery/jquery@a32cf6324f8f2190e66a687e94be9687ebf840b7 slim build with an addition of -sizzle

does not seem to be breaking anything (yet)

ref. https://github.com/xoseperez/espurna/issues/1132#issuecomment-431868924
it is slightly bigger, but better looking and no jquery dependency

rework colorpicker style as well, hide to prevent sending garbage when
lights are off. update lights module to send `lightState()` and separate
state from status payloads

yes, input[type="color"] is an option, but it does not look good

Bump npm version installed by travis
Update package-lock for latest npm version
Bump packages versions and clean-up unused
Missing datatables.js images to avoid warnings

* images for the devices
* optimized images
* fixed typo in ech1560