Add a tags edit page

[florian-h05]

In openhab/openhab-core#3646, REST endpoint to manage the semantic tabs were added.

Main UI is currently missing a page to edit those, therefore a semantic tags edit page should be added with a tree-view similar to the actual semantic model page.

[florian-h05]

@jimtng I remember you said you had some time.
Is this something you would like to have a look at?

I guess parts of the required can be re-used from the model edit page.

[jimtng]

Is this something you would like to have a look at?

This sounds interesting, but currently I have a few things brewing. I don't want to say yes to this and stop others from jumping in.

[florian-h05]

Fine. I don't think there are so many others who would jump in ...
And I currently don't have the time to start such bigger PRs.