ccls: enhancements: install default subport; add port-select functionality

[casouri (Yuan Fu)]

ccls could have some enhancements:

1. currently ccls port is a meta port and doesn't install any executable. That is confusing because people (me) type sudo port install ccls and expect ccls binary to be installed. I suggest hiding ccls port altogether to avoid confusion.

2. The two subports ccls-clang-7.0 and ccls-clang-8.0 install executables named ccls-clang-7.0 and ccls-clang-8.0 - that's confusing too because most users and programs expect the "ccls" executable. We should add a selection group and a default selection so there is an executable named ccls automatically and users can easily switch between the two subports.

[mascguy (Christopher Nielsen)]

I have an open PR to update this port, and both of these are easy enough to add. So I'll take care of this too.

[mascguy (Christopher Nielsen)]

Replying to mascguy:

I have an open PR to update this port, and both of these are easy enough to add. So I'll take care of this too.

Work completed, and added to open PR:

​15870 - ccls: update to 20220729; add clang 12 thru 14; add port-select functionality

[Christopher Nielsen <mascguy@…>]

In d80096db2db4144c4cf880d1a8a2d671baacd4ff/macports-ports (master):

ccls: update to 20220729; add clang 12 thru 14

• Use rapidjson, rather than building private version
• Install ccls-clang-10 by default, for parent port
• Add port-select functionality

Fixes: #59811