Unnecessary database packages

[glin]

@colearendt noted that we pull in some databases that R packages don't actually need, such as MySQL and MongoDB. Packages typically only need the client library.

We have separate rules for the MySQL server and client library:

• https://github.com/rstudio/r-system-requirements/blob/master/rules/mysql.json
• https://github.com/rstudio/r-system-requirements/blob/master/rules/libmysqlclient.json
• https://github.com/rstudio/r-system-requirements/blob/master/rules/mongodb.json

But the MySQL Server rule has some false positive matches, like:

Package: RMySQL
SystemRequirements: libmariadb-client-dev | libmariadb-client-lgpl-dev | libmysqlclient-dev (deb), mariadb-devel (rpm), mariadb | mysql-connector-c (brew), mysql56_dev (csw)

(\bmysql\b matches mysql-connector-c).

We should fix the patterns so that only the client libraries are pulled in when required, and only the servers are pulled in when required. Or remove the rules if the packages aren't actually required.

Packages that require MySQL:

• https://cran.r-project.org/web/packages/RMySQL/index.html
• https://cran.r-project.org/web/packages/RMariaDB/index.html
• https://cran.r-project.org/web/packages/compendiumdb/index.html
• https://cran.r-project.org/web/packages/CollapsABEL/index.html

Packages that require MongoDB:

• https://cran.r-project.org/web/packages/GeoMongo/index.html
• https://cran.r-project.org/web/packages/jSonarR/index.html