Fix NcRichText style

[julien-nc]

@juliushaertl We missed something when moving RichText in here as NcRichText.
The richtext.scss file is not used anymore. It had to be imported separately when RichText was used.
We could now simply import it in NcRichText.

@raimund-schluessler No problem with importing it, right?

Another problem raised in nextcloud/spreed#9163 is that links have the rich-text--component class and they apparently used to have the rich-text--external-link (with useMarkdown set to false). This leads to them not being underlined anymore.
@juliushaertl Apparently this appeared after @nextcloud/vue-richtext v2.0.4. Does it ring a bell? Any intentional change in the link class?

Fix nextcloud/spreed#9163

[raimund-schluessler]

@raimund-schluessler No problem with importing it, right?

I think that should be fine.

[juliusknorr]

Another problem raised in nextcloud/spreed#9163 is that links have the rich-text--component class and they apparently used to have the rich-text--external-link (with useMarkdown set to false). This leads to them not being underlined anymore.

I think the class should still be there pulled in from https://github.com/nextcloud/nextcloud-vue/blob/fix/noid/ncrichtext-style/src/components/NcRichText/autolink.js#L69
https://github.com/nextcloud/nextcloud-vue/blob/fix/noid/ncrichtext-style/src/components/NcRichText/autolink.js#L20

Apparently this appeared after @nextcloud/vue-richtext v2.0.4. Does it ring a bell? Any intentional change in the link class?

Seems quite odd, nothing I'd be aware of, but might be that another app had the style imported and now that isn't the case anymore?

[juliusknorr]

Just importing would be fine I think as well

[julien-nc]

I think I found the issue about the class. NcLink was functional and it is not anymore. It seems when rendering the component there:
https://github.com/nextcloud/nextcloud-vue/blob/master/src/components/NcRichText/placeholder.js#L46-L50
the class was not overridden when NcLink was functional. I don't know if it's an expected difference between rendering functional and non-functional components.
Anyway, as the class is systematically overridden, we always loose the initial one set in the NcLink definition.

I implemented a basic fix which does not override the class of NcLink but still set the rich-text--component class for all other components.

[nickvergessen]

Fixes missing underlining for links to github etc.
But links to 127.0.0.1 are still not clickable :(

[julien-nc]

@juliushaertl Just wanna make sure you agree with this change 😁. Are there potentially other specific cases (other components) for which the class should not be overridden?