Add links to RStudio Solutions Engineering articles in package documentation

[rich-iannone]

The following articles provide useful guides on how to use blastula in RStudio Connect:

• https://solutions.rstudio.com/post/rstudio-connect-custom-emails-with-blastula/
• https://solutions.rstudio.com/examples/blastula-overview/
• https://solutions.rstudio.com/examples/blastula/conditional-example/
• https://solutions.rstudio.com/examples/scheduling/scheduling/

They are nowhere in the function documentation and they would be useful there.

[Aariq]

New URL: https://solutions.posit.co/write-code/blastula/index.html#customized-conditional-email-workflows-on-connect