Update dependencies and prune lock files

[novellizator]

https://github.com/salsita/foosball-rating/network/alerts points to the problems and they are two fold.

• deps need to be updated

• we seem to be using both package-lock and yarn-lock. Let's delete one of them (and put it in gitignore) and be consistent

[littlewhywhat]

so at the current moment there are alerts regarding minimist 0.0.8 for root and backend package.json files.
For root package.json:

├─┬ eslint@6.8.0
│ └─┬ mkdirp@0.5.1
│   └── minimist@0.0.8 

comes from eslint 6.8.0 and it's the latest release of eslint - it actually uses this old version of mkdirp https://github.com/eslint/eslint/blob/v6.8.0/package.json#L75

should be resolved with this one eslint/eslint#13050 - then we can update eslint or we can wait for dependabot to do... :)

[littlewhywhat]

for backend/package.json:

└─┬ node-pg-migrate@4.2.2
  └─┬ mkdirp@0.5.1
    └── minimist@0.0.8 

Used by node-pg-migrate as you see but actually this is strange for me because the package uses ~1.0.0 of mkdirp - https://github.com/salsita/node-pg-migrate/blob/master/package.json#L48 that doesn't use minimist at all https://github.com/isaacs/node-mkdirp/blob/v1.0.0/package.json... I tried to reinstall but still I get old mkdirp in package-lock.json.

[littlewhywhat]

for node-pg-migrate - the problem is that in tgz package we still use mkdirp 0.5.0 therefore npm keeps installing it with minimist.

[littlewhywhat]

still need to run npm audit fix in frontend and root folders

[littlewhywhat]

fixed by #134 and #123