Text box margin should account for border thickness

Description

In text boxes, the margin between text and border cannot be controlled, and does not take border width into account. Exaggerated example:

Automatic margin should be distance from text bounding box to inner edge of border, and it would be good to have an option for the user to specify margin (or margins, separately for top/bottom/side).

Steps to reproduce

KiCad Version

Application: KiCad Schematic Editor x86_64 on x86_64

Version: 7.99.0-unknown-2cc3d8e9bc~165~ubuntu22.04.1, release build

Libraries:
	wxWidgets 3.2.1
	FreeType 2.11.1
	HarfBuzz 2.7.4
	FontConfig 2.13.1
	libcurl/7.81.0 OpenSSL/3.0.2 zlib/1.2.11 brotli/1.0.9 zstd/1.4.8 libidn2/2.3.2 libpsl/0.21.0 (+libidn2/2.3.2) libssh/0.9.6/openssl/zlib nghttp2/1.43.0 librtmp/2.3 OpenLDAP/2.5.13

Platform: Linux Mint 21.1, 64 bit, Little endian, wxGTK, cinnamon, x11

Build Info:
	Date: Feb 13 2023 10:33:15
	wxWidgets: 3.2.1 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.74.0
	OCC: 7.5.2
	Curl: 7.81.0
	ngspice: 38
	Compiler: GCC 11.3.0 with C++ ABI 1016

Build settings:
	KICAD_SPICE=ON