chore: enable live reload for changes to themes

[rpocklin]

Description

Owncloud has done a great job allowing customisations of themes without needing to make modifications directly to the owncloud-design-system 👍

This PR allows you to live reload in local development mode as you go through and change any theme(s) you are working on. (Eg. changing the colour of swatch-brand-default.)

My understanding for why it does not work by default is because the application will load the theme file via fetch at runtime from the location defined in the config.json which, typically, would be defined as follows (on the same domain as a relative url):

   "theme": "themes/aarnet/theme.json",

This content is generated from packages/web-runtime/themes/<theme_name>/theme.json and copied by rollup into the dist folder, but because it's not part of the source code of the project (retrieved via fetch as opposed to static includes via TS/JS) rollup does not monitor changes to files in these folders.

There may be a better way to do this so open to alternatives but this is an easy way to get the intended behaviour of real-time theme customisations, which makes it a very productive way to customise the look and feel.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would create a changelog item based on your changes.

[sonarcloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

32.7% Coverage
4.0% Duplication

[ownclouders]

Results for oC10SharingInternalGroupsSharingIndicator https://drone.owncloud.com/owncloud/web/18259/24/1
The following scenarios passed on retry:

• webUISharingInternalGroupsToRootSharingIndicator/shareWithGroups.feature:104

[ownclouders]

Results for oC10SharingExternal https://drone.owncloud.com/owncloud/web/18259/39/1
The following scenarios passed on retry:

• webUISharingExternal/federationSharing.feature:363

[rpocklin]

This PR is ready for review, not sure how coverage is calculated in SonarCloud but this is outside the source code of the project files.

[kulmann]

Good idea 👍🏻

[pascalwengerter]

Love it! Not a "Change" in terms of semver from my POV, though ;)

[kulmann]

True, changed it to enhancement now, thanks for the hint!

[rpocklin]

Good point, agreed!