[UI] Upgrade packages and engines

[pietdaniel]

This PR updates the following ui packages:

buefy
 - "^0.8.6"
 + "^0.9.13"
node-sass
 - "^4.14.1"
 + "^6.0.0"
sass-loader
 - "^8.0.0"
 + "^10.1.1"

It also updates the following engines:

node
 - ">= 6.0.0"
 + ">= 16.0.0"
npm
 - ">= 3.0.0"
 + ">= 8.0.0"

Some small changes were made to the webpack.*.conf.js files in order to resolve issues in building locally.

Due to the buefy upgrade, the

<template slot-scope="props">

syntax was no longer valid, being replaced with:

<b-table-column v-slot="props" ...

This PR updates all references to the modern style.

Finally, a lint error on the location of some attributes and the beforeRouteLeave function was resolved.

This PR has been tested and built locally and deployed to a live environment.

[markphelps]

Cheers 🍻 @pietdaniel !

I appreciate the help, I'm a noob when it comes to JS and keeping the libs up to date. Def can use help you can provide modernizing the JS

I created a PR against this one to update the node versions in the ITs and locally

[codecov-commenter]

Codecov Report

Merging #625 (364ef14) into master (dea84e0) will not change coverage.
The diff coverage is n/a.

❗ Current head 364ef14 differs from pull request most recent head e2893de. Consider uploading reports for the commit e2893de to get more accurate results

@@           Coverage Diff           @@
##           master     #625   +/-   ##
=======================================
  Coverage   83.43%   83.43%           
=======================================
  Files          16       16           
  Lines        1443     1443           
=======================================
  Hits         1204     1204           
  Misses        207      207           
  Partials       32       32           

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[markphelps]

@all-contributors please add @pietdaniel for code

[allcontributors]

@markphelps

I've put up a pull request to add @pietdaniel! 🎉