Add dependency check

[lshep]

warnings if too many dependencies

[LiNk-NY]

IIRC this is handled by R CMD check when there are multiple packages in the Depends field.
Should BiocCheck do more than what R CMD check provides?
If so, the guidelines should be updated first if we want to enforce that a package cannot depend on more than X # of packages.

Update: It seems this shows up when using the --as-cran flag:
R CMD check --as-cran uncoverappLib:

N  checking package dependencies (4.9s)
   Imports includes 25 non-default packages.
   Importing from so many packages makes the package vulnerable to any of
   them becoming unavailable.  Move as many as possible to Suggests and
   use conditionally.

[llrs]

Perhaps this is easily done here, but it could also be done via [_R_CHECK_EXCESSIVE_IMPORTS_](https://cran.r-project.org/doc/manuals/r-devel/R-ints.html#index-_005fR_005fCHECK_005fEXCESSIVE_005fIMPORTS_005f) = 20 on the package checker

[LiNk-NY]

Thanks Lluís!
I will check with the team about adding it to the BBS. It seems reasonable.
PS. I deleted the duplicate comment.

[lshep]

Added to SPB - Bioconductor/packagebuilder@97030b5 I'll activate it when I set up the SPB on devel post release

[llrs]

Yeh, sorry for the formatting and duplicate message. I was using a flaky internet connection. Glad this was added.