Retire BASE_SVN/base_svn in develop

[KateFriedman-NOAA]

Description

The BASE_SVN/base_svn variable and path are no longer needed. No longer use SVN since moving to Git. Now use BASE_GIT/base_git variable and path for local install locations. Retire any remaining references to BASE_SVN and base_svn from `develop.

Acceptance Criteria (Definition of Done)

References to and use of BASE_SVN and base_svn no longer exist in develop.

[KateFriedman-NOAA]

Only remaining instances of BASE_SVN or base_svn are in the workflow hosts files:

-bash-4.2$ pwd
/scratch1/NCEPDEV/global/Kate.Friedman/git/fork_feature/retire-basesvn
-bash-4.2$ grep BASE_SVN * -r
-bash-4.2$ grep base_svn * -r                                                                                                                                              
workflow/hosts/orion.yaml:base_svn: '/work/noaa/global/glopara/svn'
workflow/hosts/hera.yaml:base_svn: '/scratch1/NCEPDEV/global/glopara/svn'

Removed instance of base_svn in incoming wcoss2.yaml hosts file.

[KateFriedman-NOAA]

Removed remaining instances of base_svn from hosts files @ 5377ab3

-bash-4.2$ pwd
/scratch1/NCEPDEV/global/Kate.Friedman/git/fork_feature/retire-basesvn
-bash-4.2$ git branch
  develop
* feature/retire-basesvn
-bash-4.2$ grep BASE_SVN * -r
-bash-4.2$ grep base_svn * -r
-bash-4.2$