Code quality badges in oC10 app repos

[phil-davis]

Adjust README in each app repo to have SonarCloud code quality badges, like was already done in activity app PR https://github.com/owncloud/activity/pull/916

• remove any old Scrutinizer and codecov badges
• add "Quality Gate Status", "Security Rating" and "Coverage" badges from SonarCloud

The badges can be copy-pasted from SonarCloud projects at links like https://sonarcloud.io/dashboard?id=owncloud_announcementcenter and click on bottom-right "Get project badges"

While doing this, also:

• add .drone.yml to .gitignore like already done in https://github.com/owncloud/activity/pull/922

[swoichha]

Apps to adjust README:

This is the full list of remaining apps:

• [x] activity https://github.com/owncloud/activity/pull/916
• [x] admin_audit https://github.com/owncloud/admin_audit/pull/356
• [x] announcementcenter https://github.com/owncloud/announcementcenter/pull/162
• [x] audit_splunk https://github.com/owncloud/audit_splunk/pull/128
• [x] brute_force_protection https://github.com/owncloud/brute_force_protection/pull/150
• [x] calendar https://github.com/owncloud/calendar/pull/1161
• [x] configreport https://github.com/owncloud/configreport/pull/141
• [x] contacts https://github.com/owncloud/contacts/pull/706
• [x] customgroups https://github.com/owncloud/customgroups/pull/391
• [x] data_exporter https://github.com/owncloud/data_exporter/pull/181
• [x] diagnostics https://github.com/owncloud/diagnostics/pull/68
• [x] encryption https://github.com/owncloud/encryption/pull/230
• [x] files_antivirus https://github.com/owncloud/files_antivirus/pull/392
• [x] files_classifier https://github.com/owncloud/files_classifier/pull/431
• [x] files_external_dropbox https://github.com/owncloud/files_external_dropbox/pull/103 (not need to add badges for this)
• [x] files_external_ftp https://github.com/owncloud/files_external_ftp/pull/80
• [x] files_external_s3 https://github.com/owncloud/files_external_s3/pull/570
• [x] files_ldap_home https://github.com/owncloud/files_ldap_home/pull/44
• [x] files_lifecycle https://github.com/owncloud/files_lifecycle/pull/313/
• [x] files_onedrive https://github.com/owncloud/files_onedrive/pull/111
• [x] files_paperhive https://github.com/owncloud/files_paperhive/pull/39
• [x] files_pdfviewer https://github.com/owncloud/files_pdfviewer/pull/242
• [ ] files_primary_s3 (not need to add badges for this)
• [x] files_texteditor https://github.com/owncloud/files_texteditor/pull/338
• [x] firewall https://github.com/owncloud/firewall/pull/663
• [x] firstrunwizard https://github.com/owncloud/firstrunwizard/pull/146
• [x] guests https://github.com/owncloud/guests/pull/432
• [x] icap https://github.com/owncloud/icap/pull/14
• [x] impersonate https://github.com/owncloud/impersonate/pull/174
• [x] market https://github.com/owncloud/market/pull/637
• [x] metrics https://github.com/owncloud/metrics/pull/87
• [x] notes https://github.com/owncloud/notes/pull/377
• [x] notifications https://github.com/owncloud/notifications/pull/330
• [x] oauth2 https://github.com/owncloud/oauth2/pull/281
• [x] objectstore https://github.com/owncloud/objectstore/pull/129
• [x] openidconnect https://github.com/owncloud/openidconnect/pull/137
• [ ] ownbrander (not need to add badges for this)
• [x] password_policy https://github.com/owncloud/password_policy/pull/325
• [x] ransomware_protection https://github.com/owncloud/ransomware_protection/pull/253
• [x] richdocuments https://github.com/owncloud/richdocuments/pull/377
• [x] search_elastic https://github.com/owncloud/search_elastic/pull/196
• [x] smb_acl https://github.com/owncloud/smb_acl/pull/115
• [x] systemtags_management https://github.com/owncloud/systemtags_management/pull/86
• [x] templateeditor https://github.com/owncloud/templateeditor/pull/126
• [x] testing https://github.com/owncloud/testing/pull/161
• [x] theme-enterprise https://github.com/owncloud/theme-enterprise/pull/92
• [x] twofactor_totp https://github.com/owncloud/twofactor_totp/pull/209
• [x] user_ldap https://github.com/owncloud/user_ldap/pull/614
• [x] user_shibboleth https://github.com/owncloud/user_shibboleth/pull/313
• [x] windows_network_drive https://github.com/owncloud/windows_network_drive/pull/319
• [x] wopi https://github.com/owncloud/wopi/pull/111
• [x] workflow https://github.com/owncloud/workflow/pull/252

[phil-davis]

Done :rocket: