Update dependencies

[jankapunkt]

This PR updates dependencies and replaces underscore (which is often cause of many vulnerabilities) with native implementations.
It also updates the CI and adds our own improved minimongo.

Note, that the minimongo-cache is currently only added as package from Github (see package.json) and I will replace this with the published package, once it's published.

Therefore, this PR first requires the minimongo PR to be reviewed/merged and the new minimongo package to be published.

How can I test this PR in my setup?

First uninstall @meteorrn/core via npm uninstall --save @meteorrn/core then install this exact branch from GitHub:

$ meteor npm install --save --save-exact "git+ssh://git@github.com/meteorrn/meteor-react-native/#update-dependencies"

note the doublequotes here

[github-actions]

Closing this PR due to no activity. Feel free to reopen.

[jankapunkt]

@TheRealNate I am going to merge this now, I used this branch in our project quite some time and it works without issues. Should this be published as new major version? There are no real "breaking" changes but the update itself is quite big. What do you think?