[FIX] base,website_sale,fleet: do not use a space in xmlid

This probably a bad idea for odoo but is definitly a bad idea for pofile

As shown in gettext reference, the spaces are used as separator in po files
https://www.gnu.org/software/gettext/manual/html_node/PO-Files.html
For instance
    #: src/msgcmp.c:338 src/po-lex.c:699
    #, c-format
    msgid "found %d fatal error"
    msgstr "..."

The line "model_terms:ir.ui.view,arch_db:website_sale.search count"
was considered as two references:
- 'model_terms:ir.ui.view,arch_db:website_sale.search'
- 'count'

Correct external id of fleet, even if not translatable