Remove `BCollapse` from `GlCollapse`

We should move logic from BCollapse directly into GlCollapse.

BootstrapVue props to support

• visible

We should consider if we think it makes sense to continue supporting accordion, appear, id, is-nav, and tag props.

BootstrapVue slots to support

• default

BootstrapVue events to support

• input

We should consider if we think it makes sense to continue supporting bv::collapse::state, hidden, hide, show, and shown events.