Add phone and email link block

[SebiVPS]

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PR Checklist

• Verify if the change requires a changeset. See CONTRIBUTING.md
• Provide screenshots/screencasts if the change contains visual changes

Screenshots/screencasts

[nsams]

I remember we discussed if we need this or not, but that is years ago. We decided No back then.

[SebiVPS]

@nsams: @johnnyomair and @thomasdax98 decided that we should add these two blocks to the library. Meanwhile there are multiple implementations in many different repos around. So instead of add another copy to the comet-starter, we add it to the library and remove the other copies. The components itself are pretty common and can be used for every use case when they are needed.

[johnnyomair]

@nsams the problem with supporting mailto: and tel: in ExternalLinkBlock only is that editors don't know about them. We thought about adding a fancy UI/UX feature to fix this (e.g., detecting emails automatically and add the mailto: prefix), but couldn't come up with an elegant solution. Furthermore, editors would still need to know that they have to select "External link" in the link block for a phone number, which isn't intuitive. So we decided having two more options is the way to go.

[johnnyomair]

@SebiVPS please rebase and resolve conflicts.

[johnnyomair]

Why are the blocks in @comet/blocks-api but in @comet/cms-admin, and not @comet/blocks-admin?

[SebiVPS]

Why are the blocks in @comet/blocks-api but in @comet/cms-admin, and not @comet/blocks-admin?

@johnnyomair i put it there because there are more other blocks around in @comet/cms-admin. In @comet/blocks-admin there is only a deprecated SpaceBlockand a YoutTubeBlock.
We can move it to the other package if you want. I don't know where it really belongs.

[johnnyomair]

Why are the blocks in @comet/blocks-api but in @comet/cms-admin, and not @comet/blocks-admin?

@johnnyomair i put it there because there are more other blocks around in @comet/cms-admin. In @comet/blocks-admin there is only a deprecated SpaceBlockand a YoutTubeBlock. We can move it to the other package if you want. I don't know where it really belongs.

I'd say move it @comet/cms-api. We plan to dissolve @comet/blocks-api and @comet/blocks-admin into the respective cms packages.