added software posts images

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...te-a-new-Blog-Post/Screenshot_Review_Apps_01_20191121.png

...s/2019-12-11-SWC-Workshop-at-GFZ/xkcd_estimating_time.png

...20-01-07-contributing-in-4-simple-steps/create_folder.png

.../2020-04-15-smime-signing-of-git-commits/smime-github.png

.../2020-04-15-smime-signing-of-git-commits/smime-gitlab.png

...mg/posts/2020-04-17-online-swc-at-hzdr/view_from_home.jpg

...img/posts/2020-06-11-HackyHour/wisdom_of_the_ancients.png

...mg/posts/2020-10-15-survey-technology/ci_service_used.svg

...-15-survey-technology/participants_per_research_field.svg

.../posts/2020-10-15-survey-technology/stackoverflow_vcs.svg

...-10-15-survey-technology/sw_dev_platforms_percentages.svg

...img/posts/2020-10-15-survey-technology/vcs_percentage.svg

...hnology/vcs_usage_per_code_share_category_percentages.svg

...osts/2020-10-15-survey-technology/vcs_usage_per_field.svg

.../2020-10-15-survey-technology/vcs_usage_per_team_size.svg

...-07-survey-results-language-vcs/plot_ci_service_usage.svg

...esults-language-vcs/plot_language_by_field_normalized.svg

...-11-07-survey-results-language-vcs/plot_vcs_per_field.svg