Node 14 and NPM 7

[nickvergessen]

For more background see nextcloud/app-tutorial#319 and feel free to ask your questions there.
I just automated the PRs to set the correct engine everywhere:

• Bump node and npm version in package.json activity#594 Use npm 7 activity#593
• Bump node and npm version in package.json files_pdfviewer#429
• Bump node and npm version in package.json files_videoplayer#239
• Bump node and npm version in package.json firstrunwizard#547
• Bump node and npm version in package.json logreader#534
• Bump node and npm version in package.json notifications#1008
• Bump node and npm version in package.json password_policy#210
• Bump node and npm version in package.json privacy#638
• Bump node and npm version in package.json recommendations#412
• Bump node and npm version in package.json viewer#957
• Bump node and npm version in package.json announcementcenter#363
• Bump node and npm version in package.json deck#3139
• Bump node and npm version in package.json external#264
• Bump node and npm version in package.json files_automatedtagging#490
• Bump node and npm version in package.json files_texteditor#423
• Bump node and npm version in package.json flow_notifications#29
• Bump node and npm version in package.json groupfolders#1535
• Bump node and npm version in package.json ldap_write_support#347
• Bump node and npm version in package.json richdocuments#1610
• Bump node and npm version in package.json spreed#5785
• Bump node and npm version in package.json terms_of_service#593
• Bump node and npm version in package.json text#1663
• Bump node and npm version in package.json user_retention#367
• Bump node and npm version in package.json workflow_pdf_converter#332
• Bump node and npm version in package.json bruteforcesettings#322
• Bump node and npm version in package.json calendar#3223
• Bump node and npm version in package.json forms#989
• Bump node and npm version in package.json guests#639
• Bump node and npm version in package.json integration_discourse#14
• Bump node and npm version in package.json integration_github#24
• Bump node and npm version in package.json integration_gitlab#20
• Bump node and npm version in package.json integration_google#61
• Bump node and npm version in package.json integration_jira#18
• Bump node and npm version in package.json integration_mastodon#13
• Bump node and npm version in package.json integration_moodle#20
• Bump node and npm version in package.json integration_reddit#12
• Bump node and npm version in package.json integration_twitter#16
• Bump node and npm version in package.json integration_whiteboard#35
• Bump node and npm version in package.json integration_zammad#15
• Bump node and npm version in package.json mail#5199
• Bump node and npm version in package.json officeonline#162
• Bump node and npm version in package.json registration#315
• Bump node and npm version in package.json social#1279
• Bump node and npm version in package.json suspicious_login#486
• Bump node and npm version in package.json twofactor_totp#1125
• Bump node and npm version in package.json twofactor_u2f#902
• Bump node and npm version in package.json user_oidc#282

[PVince81]

all done, only activity remains