Change formulation (remove "section"), change import link to upload link

[pwalczysko]

See #47 for motivation.

Suggesting here to point in "General concepts" to the whole upload chapter, instead of pointing directly to "import" sub-chapter, which was bypassing the metadata upload walkthrough.

[jburel]

etc. (extra dot)

[joshmoore]

Top-level now points to top-level of upload 👍

As a side note, I have several warnings building locally:

/opt/own-guides/omero-guides/example.rst:54: WARNING: Problem with "end-before" option of "include" directive:
Text not found.
upload/docs/import-cli.rst:45: WARNING: download file not readable: /opt/own-guides/scripts/bulk.yml
/opt/own-guides/omero-guides/iviewer/docs/iviewer_rois.rst:133: WARNING: image file not readable: iviewer/docs/images/Iviewer16.png
/opt/own-guides/omero-guides/iviewer/docs/iviewer_rois.rst:136: WARNING: image file not readable: iviewer/docs/images/Iviewer17.png
/opt/own-guides/omero-guides/upload/docs/import-cli.rst:24: WARNING: duplicate label resources, other instance in /opt/own-guides/omero-guides/example_facility_manager.rst
looking for now-outdated files... none found
pickling environment... done
checking consistency... done
preparing documents... done
writing output... [100%] write_guide
generating indices... genindex done
writing additional pages... search done
copying images... [100%] upload/docs/images/metadata9.png
WARNING: cannot copy downloadable file '/opt/own-guides/omero-guides/figure/docs/../scripts/': [Errno 21] Is a directory: '/opt/own-guides/omero-guides/figure/docs/../scripts/'
copying downloadable files... [100%] upload/scripts/four-images.csv

but I don't see any relationship to this PR. Happy to see this merged. (Eventually I could imagine having some icons or maybe a workflow graphic at the top of the page.)

[pwalczysko]

#55 created for the icons.

The warnings are indeed always there - they somehow come from the submodules, and in the reasult on readthedocs there are no errors detectable corresponding to those warnings.

Thank you @joshmoore

[joshmoore]

I don't think the warnings are just a matter of the submodules, or perhaps they are but they should be fixed anyway. Migrated to #56