Fix #1226 #967: Refactoring of timeline plugin

[mspae]

Short description of changes:

• Clean timeline container so consecutive file loads don't produce empty canvases
• Refactor timeline plugin to be more like the multi canvas renderer
• Performance optimisations (as described here) for rerenders (when zooming)
• Added labelPadding parameter to configure the space between notches and labels
• Added zoomDebounce parameter to (optionally) specify a debounce timeout when zooming. (Useful for very large files
• Added jsdoc comments

Breaking in the external API:

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Breaking changes in the internal API:

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Todos/Notes:

• Performance gains should be more noticeable when Fix: Changed the fired redraw event after drawBuffer to redrew #1220 is merged (currently there is one unnecessary timeline redraw happening when zooming)
• Contains Fix: linting issues #1233 to be able to build

Related Issues and other PRs:

• Should fix the issues in Bugs with timeline rendering when using the dynamic plugin API/loading new files #1226
• Should fix Bad zooming performance when using timeline plugin #967 for v2