Address a11y issues

[will0684]

This PR contains fixes addressing the issues raised during the a11y review by the IT Accessibility Office.

Issue	Solution
a11y - Bad or no reflow on some screen resolutions	Reduce length of placeholder strings in the search bar to fit 320x256 resolutions
a11y - Focus order unpredictable	Removed flex-row-reverse from container of Reset and Filter buttons in Filter dropdown
a11y - Improperly emulating links	Fixed incorrect references in Footer.astro and i18n/ui.ts
a11y - Links must have discernible text	Links are now properly labelled and describe their purpose
a11y - New or changed content not being conveyed to Assistive Technologies	Added status to indicate when no results are found in a search or filter. Also modified the behaviour of the search text input to behave the same as the button when submitting the form. Previously the page would refresh without actually submitting the search values.
a11y - Page lacks meaningful heading structure	Changed footer H3 heading to H2 so that it exists on the same heading level as the "Help improve this tool" H2 in the CallToAction.
a11y - Page section missing lang attribute #1	Added translation strings for alt-text of heading logo
a11y - Page section missing lang attribute #2	Added lang attributes with appropriate values to the language toggle anchors
a11y - Using structural markup in a way that does not represent relationships in the content	Added labels to pagination controls for better accessibility

[Fbasham]

As far as I can tell this runs fine. Thank you for inheriting this work and finishing it off.