Milestone 2ga Consolidate CSS of file-explorer

[timea-solid]

File Explorer contains more panes and elements, each of which needs to be updated.
IMPORTANT - some panes are only visible once Power User is active.

PRs

• dataContentPane, RDFXMLPane, n3Pane, humanReadablePane, padPane, defaultPane, sharingPane, schedulePane, imagePane, formPane are in solid-panes Refactor separate the styles for the FileExplorer panes solid-panes#566
• Source-pane Refactor styles to CSS source-pane#126
• folder-pane Refactor styles into separate CSS folder-pane#160

Part of the file type display:

• Data Content pane

• RDFXML pane

• n3 pane

• humanReadable pane

• source pane

• pad pane

• internal pane

• default pane
  Sharing pane:

• sharing pane
  Schedule

• Schedule pane
  Image pane - visible when an image is uploaded in the explorer

• Image pane
  Folder Pane

• Folder Pane
  Form Pane

• Form Pane

TODO for each:

• extracting all inline CSS in dedicated CSS files (example in profile-pane) Very important is to create dedicated CSS pane names. Example: if you use the .warning, its CSS will be coming from mash.css so create a dedicated .warning-contact for it if the one in mash.css does not fit.
• making sure the CSS is part of the release. Maybe we need a webpack) build, and an accompanying entry file (example index.ts)
• using already available CSS variables from mashlib light theme and documenting in the PR what other CSS variables could be moved to the main mashlib theme

[SharonStrats]

The following have no style in them. No css file created.
RDFXMLPane
n3Pane
defaultPane
sharingPane