Add email button to working groups

[HarHarLinks]

Some working groups are reachable via email. The working groups page needs to be extended to support this.

There should be an email button after the matrix button:

matrix.org/templates/governing-board/working_groups.html

Lines 43 to 49 in ef8f7e3

	<a href="https://matrix.to/#/{{ wg.matrix_room_alias }}" class="button"><svg viewBox="0 0 32 32"
	xmlns="http://www.w3.org/2000/svg">
	<path d="M 30,2.0000001 V 30 h -1 -2 v 2 h 5 V -3.3333334e-8 L 27,0 v 2 z" />
	<path
	d="M 9.9515939,10.594002 V 12.138 h 0.043994 c 0.3845141,-0.563728 0.8932271,-1.031728 1.4869981,-1.368 0.580003,-0.322998 1.244999,-0.485 1.993002,-0.485 0.72,0 1.376999,0.139993 1.971998,0.42 0.595,0.279004 1.047001,0.771001 1.355002,1.477001 0.338003,-0.500001 0.795999,-0.941 1.376999,-1.323001 0.579999,-0.382998 1.265998,-0.574 2.059998,-0.574 0.602003,0 1.160002,0.074 1.674002,0.220006 0.514,0.148006 0.953998,0.382998 1.321999,0.706998 0.36601,0.322999 0.653001,0.746 0.859,1.268002 0.205001,0.521998 0.307994,1.15 0.307994,1.887001 v 7.632997 h -3.127 v -6.463997 c 0,-0.383002 -0.01512,-0.743002 -0.04399,-1.082003 -0.02079,-0.3072 -0.103219,-0.607113 -0.242003,-0.881998 -0.133153,-0.25081 -0.335962,-0.457777 -0.584001,-0.596002 -0.257008,-0.146003 -0.605998,-0.220006 -1.046997,-0.220006 -0.440002,0 -0.796003,0.085 -1.068,0.253002 -0.272013,0.170003 -0.485001,0.390002 -0.639001,0.662003 -0.159119,0.287282 -0.263585,0.601602 -0.307994,0.926997 -0.05197,0.346923 -0.07801,0.697217 -0.07801,1.048002 v 6.353999 h -3.128005 v -6.398 c 0,-0.338003 -0.0072,-0.673001 -0.02116,-1.004001 -0.01134,-0.313663 -0.07487,-0.623229 -0.187994,-0.915999 -0.107943,-0.276623 -0.300435,-0.512126 -0.550001,-0.673001 -0.25799,-0.168 -0.636,-0.253002 -1.134999,-0.253002 -0.198123,0.0083 -0.394383,0.04195 -0.584002,0.100006 -0.258368,0.07446 -0.498455,0.201827 -0.704999,0.373985 -0.227981,0.183987 -0.421999,0.449 -0.583997,0.794003 -0.161008,0.345978 -0.242003,0.797998 -0.242003,1.356998 v 6.618999 H 6.99942 V 10.590001 Z" />
	<path d="M 2,2.0000001 V 30 h 3 v 2 H 0 V 9.2650922e-8 L 5,0 v 2 z" />
	</svg><span>Chat</span></a>

Like the charter and matrix buttons, the email button appears only conditionally when an address is set in https://github.com/matrix-org/matrix.org/blob/main/content/foundation/working-groups/working_groups.toml.

The email button continues the layout of the charter and matrix buttons. It should use an appropriate email icon. It is unclear if we already have such an icon; if not, we need to add one that has an appropriate license etc.

[Ritesh051]

assing me