Provide installation instructions in the README

[augusto-herrmann]

As commented in the Frictionless Data #random channel.

For anyone using VSCodium, and who has never written a VSCode extension, it might not be so obvious how to install. These instructions should help those people get it running easier, without the extra steps of the dev build, if they just want to try the extension and not necessarily develop it.

[RandomFractals]

@augusto-herrmann thanks for your PR on docs!

As mentioned in that chat we had I don't plan to package or publish this extension for VSCodium or other VSCode IDE flavors and marketplaces.

What is offered now is clear instructions on how to install it from local .vsix package in our dev build docs (& you don't have to build it :)

https://github.com/RandomFractals/tabular-data-viewer#dev-build

Direct link for those installation instructions: https://code.visualstudio.com/docs/editor/extension-marketplace#_install-from-a-vsix

You can download this extension installation package from releases here:

https://github.com/RandomFractals/tabular-data-viewer/releases

or from VS Marketplace Version History tab:

https://marketplace.visualstudio.com/items?itemName=RandomFractalsInc.tabular-data-viewer

I will close this PR & will add Installation instructions section to my README.md in the next release similar to what I have done for GeoDataViewer as an example:

https://github.com/RandomFractals/geo-data-viewer#installation

Thanks for bringing this up once again 🙂