Cleanup before CRAN release

[e-kotov]

@ilyabo hi! I made some changes to the package:

• implemented and documented processing of the time column, so that users only need to create it in datetime or date type in R and it is automatically converted to UNIX time and used in the widget

• documented the flowmapblue function with examples

• created vignette based on the examples from above with gifs for website and static pngs for the CRAN vignette

• created a pkgdown website for the package that can be auto-published using GitHub action (action pushed to branch too) assuming you are willing to host the website using GitHub pages at https://flowmapblue.github.io/flowmapblue.R (needs to be turned on in https://github.com/FlowmapBlue/flowmapblue.R/settings/pages and set to deploy from branch and set to gh-pages branch, which I already created with the pre-rendered website).

• added opengraph card (that shows up when the link is shared on social media). It will show up for https://flowmapblue.github.io/flowmapblue.R automatically, for GitHub repo link https://github.com/FlowmapBlue/flowmapblue.R/, you need to manually upload it from here https://github.com/FlowmapBlue/flowmapblue.R/blob/prep-for-CRAN-release/man/figures/opengraph-card.png into the Social preview section in repo settings https://github.com/FlowmapBlue/flowmapblue.R/settings

• added GitHub action for CI/CD to autocheck any future commits/PRs with R CMD Check

• cleaned up description and added metadata, as well as CRAN comments for submission

• properly bundled the example data as ch_locations and ch_flows, they are now available as exported objects in the package. Note: would be great to reference the source of this data for completeness of the documentation.

[ilyabo]

Thanks @e-kotov!

lgtm, I just noticed a few URL which should be changed.
I enabled google pages and uploaded the preview image.

[e-kotov]

@ilyabo sorry about the links to my other package, I will regenerate the metadata. It go in there while i was copying over some code for reuse.

[e-kotov]

Closes #2 .

[ilyabo]

No worries. I will need to change the FlowmapBlue project config (namely convert it to a monorepo and publish a library, right now it's a nextjs app). Will try to find time for it.

[e-kotov]

@ilyabo

I enabled google pages and uploaded the preview image.

great! Final thing to do is to add https://flowmapblue.github.io/flowmapblue.R/ (or just enable automatic URL to gh-pages) in the front page repo settings. Like so:

I will also add this gh-pages link to package readme and metadata and submit to CRAN.