File ids and other ids as strings

[PVince81]

In OCIS file ids and other ids can be base64 strings instead of numbers.

This means we cannot use them in HTML ids or other places where we assume that they are simple numbers.

We should replace their usages with a different field, not sure which.
Maybe we can introduce a new "key" field that gets populated after loading the data and use that instead ?

[PVince81]

A few relevant occurrences I found:

apps/files/src/components/FilesLists/RowActionsDropdown.vue|4 col 54| :boundary="`#files-file-list-action-button-${item.id}-active`"
apps/files/src/components/FilesLists/RowActionsDropdown.vue|6 col 52| :toggle="`#files-file-list-action-button-${item.id}-active`"
apps/files/src/components/FileLinkSidebar.vue|273 col 49| return textUtils.naturalSortCompare(l1.id + '', l2.id + '')
apps/files/src/components/FileList.vue|34 col 170| <oc-grid :ref="index === 0 ? 'firstRow' : null" gutter="small" flex class="uk-padding-small oc-border-top" :class="_rowClasses(item)" :id="'file-row-' + item.id">
apps/files/src/components/FileList.vue|47 col 52| :id="actionsDropdownButtonId(item.id, active)"
apps/files/src/components/FileList.vue|188 col 45| this.$scrollTo(`#file-row-${file.id}`, 500, {
apps/files/src/components/AllFilesList.vue|211 col 45| this.$scrollTo(`#file-row-${file.id}`, 500, {

I've excluded the cases where ids are used in Vue's "key" attributes as I believe these should be safe as they can be arbitrary strings.

[PVince81]

Fix is here #3248