create a portal-intro or how-to page

[mobb]

started page here:

/webpages/4_upload/portal_how_to.md

For more, see email from Stace, 2018-06-21

eg,

Regarding a test interface for rendering your EML into the format generally
used for our Data Portal, there are two options:

1. Use our staging environment (https://portal-s.edirepository.org/nis) for
   the full treatment -- you would be able to search against your metadata, as
   well as view it in the test environment; or
2. Use a little-known preview tool that is accessible at the following
   link: https://portal.edirepository.org/nis/metadataPreviewer.jsp

[cgries]

EML distribution element for manual data file upload in portal:

EML distribution element needs to be omitted completely when manually uploading the data files. Do not use distribution>offline>local computer. PASTA will not replace this with the new location but add another distribution element. I.e., the metadata in PASTA will have two distribution elements, one saying offline and not accessible, the other with the proper link to the data table.

[mobb]

DOI: landing page must show, so there must be public metadata. (non-public entities are OK, get a DOI)

[mobb]

DataONE: all entities must be public in order for metadata to be aggregated there.